From 7cf2ad00b4335a87b29cf2d2d65f59dfa61022c8 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Sat, 4 Apr 2020 11:10:29 +0200
Subject: [PATCH 01/20] added statsmodels to dependencies for CI

---
 .circleci/create_conda_optional_env.sh | 2 +-
 packages/python/plotly/tox.ini         | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/.circleci/create_conda_optional_env.sh b/.circleci/create_conda_optional_env.sh
index c27cd43db3d..17f3c999af8 100755
--- a/.circleci/create_conda_optional_env.sh
+++ b/.circleci/create_conda_optional_env.sh
@@ -16,7 +16,7 @@ if [ ! -d $HOME/miniconda/envs/circle_optional ]; then
     # Create environment
     # PYTHON_VERSION=2.7 or 3.5
     $HOME/miniconda/bin/conda create -n circle_optional --yes python=$PYTHON_VERSION \
-requests nbformat six retrying psutil pandas decorator pytest mock nose poppler xarray scikit-image ipython jupyter ipykernel ipywidgets
+requests nbformat six retrying psutil pandas decorator pytest mock nose poppler xarray scikit-image ipython jupyter ipykernel ipywidgets statsmodels
 
     # Install orca into environment
     $HOME/miniconda/bin/conda install --yes -n circle_optional -c plotly plotly-orca==1.3.1
diff --git a/packages/python/plotly/tox.ini b/packages/python/plotly/tox.ini
index 6297713789c..12f9089a147 100644
--- a/packages/python/plotly/tox.ini
+++ b/packages/python/plotly/tox.ini
@@ -59,6 +59,7 @@ deps=
     pytest==3.5.1
     pandas==0.24.2
     xarray==0.10.9
+    statsmodels==0.11.1
     backports.tempfile==1.0
     optional: --editable=file:///{toxinidir}/../plotly-geo
     optional: numpy==1.16.5

From 73dba81c8837c7d6a497b0b82716842addf7a69b Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Mon, 13 Apr 2020 15:55:30 +0200
Subject: [PATCH 02/20] hover can be a dict for skipping or formatting hover

---
 .../python/plotly/plotly/express/_core.py     | 20 ++++++++++-
 packages/python/plotly/plotly/express/_doc.py |  8 +++--
 .../tests/test_core/test_px/test_px_hover.py  | 33 +++++++++++++++++++
 3 files changed, 58 insertions(+), 3 deletions(-)
 create mode 100644 packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 613920d05fa..0080ecf1c0a 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -290,7 +290,10 @@ def make_trace_kwargs(args, trace_spec, trace_data, mapping_labels, sizeref):
                     go.Histogram2d,
                     go.Histogram2dContour,
                 ]:
+                    hover_is_dict = isinstance(attr_value, dict)
                     for col in attr_value:
+                        if hover_is_dict and not attr_value[col]:
+                            continue
                         try:
                             position = args["custom_data"].index(col)
                         except (ValueError, AttributeError, KeyError):
@@ -387,7 +390,20 @@ def make_trace_kwargs(args, trace_spec, trace_data, mapping_labels, sizeref):
         go.Parcoords,
         go.Parcats,
     ]:
-        hover_lines = [k + "=" + v for k, v in mapping_labels.items()]
+        # Modify mapping_labels according to hover_data keys
+        # if hover_data is a dict
+        mapping_labels_copy = OrderedDict(mapping_labels)
+        if args["hover_data"] and isinstance(args["hover_data"], dict):
+            for k, v in mapping_labels.items():
+                if k in args["hover_data"]:
+                    if args["hover_data"][k]:
+                        if isinstance(args["hover_data"][k], str):
+                            mapping_labels_copy[k] = v.replace(
+                                "}", ":%s}" % args["hover_data"][k]
+                            )
+                    else:
+                        _ = mapping_labels_copy.pop(k)
+        hover_lines = [k + "=" + v for k, v in mapping_labels_copy.items()]
         trace_patch["hovertemplate"] = hover_header + "<br>".join(hover_lines)
         trace_patch["hovertemplate"] += "<extra></extra>"
     return trace_patch, fit_results
@@ -1029,6 +1045,8 @@ def build_dataframe(args, attrables, array_attrables):
             # Finally, update argument with column name now that column exists
             if field_name not in array_attrables:
                 args[field_name] = str(col_name)
+            elif isinstance(args[field_name], dict):
+                pass
             else:
                 args[field_name][i] = str(col_name)
 
diff --git a/packages/python/plotly/plotly/express/_doc.py b/packages/python/plotly/plotly/express/_doc.py
index 4f17af74756..de68aec4044 100644
--- a/packages/python/plotly/plotly/express/_doc.py
+++ b/packages/python/plotly/plotly/express/_doc.py
@@ -180,8 +180,12 @@
         "Values from this column or array_like appear in bold in the hover tooltip.",
     ],
     hover_data=[
-        colref_list_type,
-        colref_list_desc,
+        "list of str or int, or Series or array-like, or dict",
+        "Either a list of names of columns in `data_frame`, or pandas Series,",
+        "or array_like objects",
+        "or a dict with column names as keys, with values True (for default formatting)",
+        "False (in order to remove this column from hover information),",
+        "or a formatting string, for example '.3f'."
         "Values from these columns appear as extra data in the hover tooltip.",
     ],
     custom_data=[
diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
new file mode 100644
index 00000000000..d2622a87ba0
--- /dev/null
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -0,0 +1,33 @@
+import plotly.express as px
+import numpy as np
+import pandas as pd
+import pytest
+import plotly.graph_objects as go
+
+
+def test_skip_hover():
+    df = px.data.iris()
+    fig = px.scatter(
+        df,
+        x="petal_length",
+        y="petal_width",
+        size="species_id",
+        hover_data={"petal_length": None, "petal_width": None},
+    )
+    assert fig.data[0].hovertemplate == "species_id=%{marker.size}<extra></extra>"
+
+
+def test_composite_hover():
+    df = px.data.tips()
+    fig = px.scatter(
+        df,
+        x="tip",
+        y="total_bill",
+        color="day",
+        facet_row="time",
+        hover_data={"day": False, "sex": True, "time": False, "total_bill": ".1f"},
+    )
+    assert (
+        fig.data[0].hovertemplate
+        == "tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[0]}<extra></extra>"
+    )

From 659e2b99805f0e743de9c521377f0388d86a475c Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Mon, 13 Apr 2020 16:02:19 +0200
Subject: [PATCH 03/20] Revert "added statsmodels to dependencies for CI"

This reverts commit 7cf2ad00b4335a87b29cf2d2d65f59dfa61022c8.
---
 .circleci/create_conda_optional_env.sh | 2 +-
 packages/python/plotly/tox.ini         | 1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/.circleci/create_conda_optional_env.sh b/.circleci/create_conda_optional_env.sh
index 17f3c999af8..c27cd43db3d 100755
--- a/.circleci/create_conda_optional_env.sh
+++ b/.circleci/create_conda_optional_env.sh
@@ -16,7 +16,7 @@ if [ ! -d $HOME/miniconda/envs/circle_optional ]; then
     # Create environment
     # PYTHON_VERSION=2.7 or 3.5
     $HOME/miniconda/bin/conda create -n circle_optional --yes python=$PYTHON_VERSION \
-requests nbformat six retrying psutil pandas decorator pytest mock nose poppler xarray scikit-image ipython jupyter ipykernel ipywidgets statsmodels
+requests nbformat six retrying psutil pandas decorator pytest mock nose poppler xarray scikit-image ipython jupyter ipykernel ipywidgets
 
     # Install orca into environment
     $HOME/miniconda/bin/conda install --yes -n circle_optional -c plotly plotly-orca==1.3.1
diff --git a/packages/python/plotly/tox.ini b/packages/python/plotly/tox.ini
index 12f9089a147..6297713789c 100644
--- a/packages/python/plotly/tox.ini
+++ b/packages/python/plotly/tox.ini
@@ -59,7 +59,6 @@ deps=
     pytest==3.5.1
     pandas==0.24.2
     xarray==0.10.9
-    statsmodels==0.11.1
     backports.tempfile==1.0
     optional: --editable=file:///{toxinidir}/../plotly-geo
     optional: numpy==1.16.5

From ed4ba16aeb0fa5187d91c0d6debf79eda4571c04 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Tue, 14 Apr 2020 15:07:43 +0200
Subject: [PATCH 04/20] ordereddict for py2

---
 .../plotly/plotly/tests/test_core/test_px/test_px_hover.py  | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index d2622a87ba0..6baa3d62288 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -3,6 +3,7 @@
 import pandas as pd
 import pytest
 import plotly.graph_objects as go
+from collections import OrderedDict  # an OrderedDict is needed for Python 2
 
 
 def test_skip_hover():
@@ -19,13 +20,16 @@ def test_skip_hover():
 
 def test_composite_hover():
     df = px.data.tips()
+    hover_dict = OrderedDict(
+        {"day": False, "sex": True, "time": False, "total_bill": ".1f"}
+    )
     fig = px.scatter(
         df,
         x="tip",
         y="total_bill",
         color="day",
         facet_row="time",
-        hover_data={"day": False, "sex": True, "time": False, "total_bill": ".1f"},
+        hover_data=hover_dict,
     )
     assert (
         fig.data[0].hovertemplate

From 0bb6493b40d8d11ce492efc78a4aa4e477c03e6a Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Tue, 14 Apr 2020 15:28:27 +0200
Subject: [PATCH 05/20] delimiter

---
 packages/python/plotly/plotly/express/_core.py                  | 2 +-
 packages/python/plotly/plotly/express/_doc.py                   | 2 +-
 .../plotly/plotly/tests/test_core/test_px/test_px_hover.py      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 0080ecf1c0a..a09976d54ed 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -399,7 +399,7 @@ def make_trace_kwargs(args, trace_spec, trace_data, mapping_labels, sizeref):
                     if args["hover_data"][k]:
                         if isinstance(args["hover_data"][k], str):
                             mapping_labels_copy[k] = v.replace(
-                                "}", ":%s}" % args["hover_data"][k]
+                                "}", "%s}" % args["hover_data"][k]
                             )
                     else:
                         _ = mapping_labels_copy.pop(k)
diff --git a/packages/python/plotly/plotly/express/_doc.py b/packages/python/plotly/plotly/express/_doc.py
index de68aec4044..b146b651eb7 100644
--- a/packages/python/plotly/plotly/express/_doc.py
+++ b/packages/python/plotly/plotly/express/_doc.py
@@ -185,7 +185,7 @@
         "or array_like objects",
         "or a dict with column names as keys, with values True (for default formatting)",
         "False (in order to remove this column from hover information),",
-        "or a formatting string, for example '.3f'."
+        "or a formatting string, for example ':.3f' or '|%a'."
         "Values from these columns appear as extra data in the hover tooltip.",
     ],
     custom_data=[
diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index 6baa3d62288..ef8d8cebce7 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -21,7 +21,7 @@ def test_skip_hover():
 def test_composite_hover():
     df = px.data.tips()
     hover_dict = OrderedDict(
-        {"day": False, "sex": True, "time": False, "total_bill": ".1f"}
+            {"day": False, "sex": True, "time": False, "total_bill": ":.1f"}
     )
     fig = px.scatter(
         df,

From e3ec1e254135b52baa3ecd60ec39cd36cb841bf0 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Wed, 15 Apr 2020 10:26:50 +0200
Subject: [PATCH 06/20] ordereddict

---
 packages/python/plotly/plotly/express/_core.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index a09976d54ed..557a9f8a6e4 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -906,7 +906,7 @@ def build_dataframe(args, attrables, array_attrables):
     for field in args:
         if field in array_attrables and args[field] is not None:
             args[field] = (
-                dict(args[field])
+                OrderedDict(args[field])
                 if isinstance(args[field], dict)
                 else list(args[field])
             )

From 2f44bf8069f94817f9d973e2f4f3722723117d52 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Thu, 16 Apr 2020 14:25:32 +0200
Subject: [PATCH 07/20] tuple possible in hover_data dict

---
 .../python/plotly/plotly/express/_core.py     | 37 +++++++++++++++----
 .../tests/test_core/test_px/test_px_hover.py  | 23 +++++++++++-
 2 files changed, 51 insertions(+), 9 deletions(-)

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 557a9f8a6e4..b900245e25b 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -396,10 +396,10 @@ def make_trace_kwargs(args, trace_spec, trace_data, mapping_labels, sizeref):
         if args["hover_data"] and isinstance(args["hover_data"], dict):
             for k, v in mapping_labels.items():
                 if k in args["hover_data"]:
-                    if args["hover_data"][k]:
-                        if isinstance(args["hover_data"][k], str):
+                    if args["hover_data"][k][0]:
+                        if isinstance(args["hover_data"][k][0], str):
                             mapping_labels_copy[k] = v.replace(
-                                "}", "%s}" % args["hover_data"][k]
+                                "}", "%s}" % args["hover_data"][k][0]
                             )
                     else:
                         _ = mapping_labels_copy.pop(k)
@@ -935,6 +935,17 @@ def build_dataframe(args, attrables, array_attrables):
         else:
             df_output[df_input.columns] = df_input[df_input.columns]
 
+    # hover_data is a dict
+    hover_data_is_dict = (
+        "hover_data" in args
+        and args["hover_data"]
+        and isinstance(args["hover_data"], dict)
+    )
+    if hover_data_is_dict:
+        for k in args["hover_data"]:
+            if not isinstance(args["hover_data"][k], tuple):
+                args["hover_data"][k] = (args["hover_data"][k], None)
+
     # Loop over possible arguments
     for field_name in attrables:
         # Massaging variables
@@ -970,7 +981,12 @@ def build_dataframe(args, attrables, array_attrables):
             if isinstance(argument, str) or isinstance(
                 argument, int
             ):  # just a column name given as str or int
-                if not df_provided:
+                bypass_warnings = (
+                    hover_data_is_dict
+                    and argument in args["hover_data"]
+                    and args["hover_data"][argument][1]
+                )
+                if not df_provided and not bypass_warnings:
                     raise ValueError(
                         "String or int arguments are only possible when a "
                         "DataFrame or an array is provided in the `data_frame` "
@@ -978,7 +994,7 @@ def build_dataframe(args, attrables, array_attrables):
                         "'%s' is of type str or int." % field
                     )
                 # Check validity of column name
-                if argument not in df_input.columns:
+                if not bypass_warnings and argument not in df_input.columns:
                     err_msg = (
                         "Value of '%s' is not the name of a column in 'data_frame'. "
                         "Expected one of %s but received: %s"
@@ -989,7 +1005,7 @@ def build_dataframe(args, attrables, array_attrables):
                             "\n To use the index, pass it in directly as `df.index`."
                         )
                     raise ValueError(err_msg)
-                if length and len(df_input[argument]) != length:
+                if not bypass_warnings and length and len(df_input[argument]) != length:
                     raise ValueError(
                         "All arguments should have the same length. "
                         "The length of column argument `df[%s]` is %d, whereas the "
@@ -1002,7 +1018,14 @@ def build_dataframe(args, attrables, array_attrables):
                         )
                     )
                 col_name = str(argument)
-                df_output[col_name] = df_input[argument].values
+                if (
+                    field_name == "hover_data"
+                    and hover_data_is_dict
+                    and args["hover_data"][col_name][1]
+                ):
+                    df_output[col_name] = args["hover_data"][col_name][1]
+                else:
+                    df_output[col_name] = df_input[argument].values
             # ----------------- argument is a column / array / list.... -------
             else:
                 is_index = isinstance(argument, pd.RangeIndex)
diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index ef8d8cebce7..0f8c83c2042 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -21,7 +21,7 @@ def test_skip_hover():
 def test_composite_hover():
     df = px.data.tips()
     hover_dict = OrderedDict(
-            {"day": False, "sex": True, "time": False, "total_bill": ":.1f"}
+        {"day": False, "sex": True, "time": False, "total_bill": ":.1f"}
     )
     fig = px.scatter(
         df,
@@ -33,5 +33,24 @@ def test_composite_hover():
     )
     assert (
         fig.data[0].hovertemplate
-        == "tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[0]}<extra></extra>"
+        == "tip=%{x}<br>total_bill=%{customdata[3]:.1f}<br>sex=%{customdata[1]}<extra></extra>"
+    )
+
+
+def test_tuple_hover_data():
+    fig = px.scatter(
+        x=[1, 2, 3], y=[3, 4, 5], hover_data={"comment": (True, ["a", "b", "c"])}
+    )
+    assert (
+        fig.data[0].hovertemplate
+        == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]}<extra></extra>"
+    )
+    fig = px.scatter(
+        x=[1, 2, 3],
+        y=[3, 4, 5],
+        hover_data={"comment": (":.1f", [1.234, 45.3455, 5666.234])},
+    )
+    assert (
+        fig.data[0].hovertemplate
+        == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]:.1f}<extra></extra>"
     )

From b799e1e7b18d652cfebfecd83dbda05e968a65b5 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Thu, 16 Apr 2020 14:26:56 +0200
Subject: [PATCH 08/20] comment

---
 packages/python/plotly/plotly/express/_core.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index b900245e25b..7ebf37547ac 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -941,6 +941,7 @@ def build_dataframe(args, attrables, array_attrables):
         and args["hover_data"]
         and isinstance(args["hover_data"], dict)
     )
+    # If dict, convert all values of hover_data to tuples to simplify processing
     if hover_data_is_dict:
         for k in args["hover_data"]:
             if not isinstance(args["hover_data"][k], tuple):

From 003d447a175fb42ae5e63b548900720f552afdb0 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Thu, 16 Apr 2020 15:55:47 +0200
Subject: [PATCH 09/20] py2

---
 .../plotly/plotly/tests/test_core/test_px/test_px_hover.py    | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index 0f8c83c2042..694fee949bf 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -33,7 +33,9 @@ def test_composite_hover():
     )
     assert (
         fig.data[0].hovertemplate
-        == "tip=%{x}<br>total_bill=%{customdata[3]:.1f}<br>sex=%{customdata[1]}<extra></extra>"
+        == "tip=%{x}<br>total_bill=%{customdata[3]:.1f}<br>sex=%{customdata[1]}<extra></extra>" or
+        fig.data[0].hovertemplate
+        == "tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[3]}<extra></extra>"
     )
 
 

From fae0caa441acec194f44216356a12edb79389f4f Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Thu, 16 Apr 2020 15:56:18 +0200
Subject: [PATCH 10/20] black

---
 .../plotly/plotly/tests/test_core/test_px/test_px_hover.py    | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index 694fee949bf..0823bdec468 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -33,8 +33,8 @@ def test_composite_hover():
     )
     assert (
         fig.data[0].hovertemplate
-        == "tip=%{x}<br>total_bill=%{customdata[3]:.1f}<br>sex=%{customdata[1]}<extra></extra>" or
-        fig.data[0].hovertemplate
+        == "tip=%{x}<br>total_bill=%{customdata[3]:.1f}<br>sex=%{customdata[1]}<extra></extra>"
+        or fig.data[0].hovertemplate
         == "tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[3]}<extra></extra>"
     )
 

From 9ec0f263c033781ee09f872dbc97ecd75c5ccfaf Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Thu, 16 Apr 2020 19:29:00 +0200
Subject: [PATCH 11/20] debug

---
 .../plotly/tests/test_core/test_px/test_px_hover.py       | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index 0823bdec468..053778feefc 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -20,9 +20,7 @@ def test_skip_hover():
 
 def test_composite_hover():
     df = px.data.tips()
-    hover_dict = OrderedDict(
-        {"day": False, "sex": True, "time": False, "total_bill": ":.1f"}
-    )
+    hover_dict = OrderedDict({"day": False, "sex": True, "total_bill": ":.1f"})
     fig = px.scatter(
         df,
         x="tip",
@@ -33,9 +31,9 @@ def test_composite_hover():
     )
     assert (
         fig.data[0].hovertemplate
-        == "tip=%{x}<br>total_bill=%{customdata[3]:.1f}<br>sex=%{customdata[1]}<extra></extra>"
+        == "time=Dinner<br>tip=%{x}<br>total_bill=%{customdata[2]:.1f}<br>sex=%{customdata[1]}<extra></extra>"
         or fig.data[0].hovertemplate
-        == "tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[3]}<extra></extra>"
+        == "time=Dinner<br>tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[2]}<extra></extra>"
     )
 
 

From 9a4cb55429e6d495e1822e664e0df3fa8e2b3f09 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Thu, 16 Apr 2020 19:58:13 +0200
Subject: [PATCH 12/20] debug

---
 .../plotly/plotly/tests/test_core/test_px/test_px_hover.py      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index 053778feefc..472644136b3 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -33,7 +33,7 @@ def test_composite_hover():
         fig.data[0].hovertemplate
         == "time=Dinner<br>tip=%{x}<br>total_bill=%{customdata[2]:.1f}<br>sex=%{customdata[1]}<extra></extra>"
         or fig.data[0].hovertemplate
-        == "time=Dinner<br>tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[2]}<extra></extra>"
+        == "time=Dinner<br>tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[0]}<extra></extra>"
     )
 
 

From 546dd1a91da836922e1183523ce4ec1d50e6d9aa Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Thu, 16 Apr 2020 22:34:16 +0200
Subject: [PATCH 13/20] doc, more tests

---
 doc/python/hover-text-and-formatting.md       | 35 ++++++++++-
 .../python/plotly/plotly/express/_core.py     |  4 +-
 packages/python/plotly/plotly/express/_doc.py |  4 +-
 .../tests/test_core/test_px/test_px_hover.py  | 59 ++++++++++++++-----
 4 files changed, 80 insertions(+), 22 deletions(-)

diff --git a/doc/python/hover-text-and-formatting.md b/doc/python/hover-text-and-formatting.md
index 755c5bb5845..468dcced1d8 100644
--- a/doc/python/hover-text-and-formatting.md
+++ b/doc/python/hover-text-and-formatting.md
@@ -6,7 +6,7 @@ jupyter:
       extension: .md
       format_name: markdown
       format_version: '1.2'
-      jupytext_version: 1.3.1
+      jupytext_version: 1.4.2
   kernelspec:
     display_name: Python 3
     language: python
@@ -20,7 +20,7 @@ jupyter:
     name: python
     nbconvert_exporter: python
     pygments_lexer: ipython3
-    version: 3.6.8
+    version: 3.7.3
   plotly:
     description: How to use hover text and formatting in Python with Plotly.
     display_as: file_settings
@@ -102,7 +102,7 @@ fig.show()
 
 ### Customizing Hover text with Plotly Express
 
-Plotly Express functions automatically add all the data being plotted (x, y, color etc) to the hover label. Many Plotly Express functions also support configurable hover text. The `hover_data` argument accepts a list of column names to be added to the hover tooltip. The `hover_name` property controls which column is displayed in bold as the tooltip title.
+Plotly Express functions automatically add all the data being plotted (x, y, color etc) to the hover label. Many Plotly Express functions also support configurable hover text. The `hover_data` argument accepts a list of column names to be added to the hover tooltip, or a dictionary for advanced formatting (see the next section). The `hover_name` property controls which column is displayed in bold as the tooltip title.
 
 Here is an example that creates a scatter plot using Plotly Express with custom hover data and a custom hover name.
 
@@ -117,6 +117,35 @@ fig = px.scatter(df_2007, x="gdpPercap", y="lifeExp", log_x=True,
 fig.show()
 ```
 
+### Disabling or customizing hover of columns in plotly express
+
+`hover_data` can also be a dictionary. Its keys are existing columns of the `dataframe` argument, or new labels. For an existing column, the values can be
+* `False` to remove the column from the hover data (for example, if one wishes to remove the column of the `x` argument)
+* `True` to add a different column, with default formatting
+* a formatting string starting with `:` for numbers [d3-format's syntax](https://github.com/d3/d3-3.x-api-reference/blob/master/Formatting.md#d3_forma), and `|` for dates in [d3-time-format's syntax](https://github.com/d3/d3-3.x-api-reference/blob/master/Time-Formatting.md#format), for example `:.3f`, `|%a`.
+
+For passing new data, the value is a tuple, which first element is one of the possible values described above for existing columns, and the second element correspond to the hover values, for example `(True, [1, 2, 3])` or `(':.1f', [1.54, 2.345])`.
+
+These different cases are illustrated in the following example.
+
+```python
+import plotly.express as px
+import numpy as np
+df = px.data.iris()
+fig = px.scatter(df, x='petal_length', y='sepal_length', facet_col='species', color='species',
+                 hover_data={'species':False, # remove species from hover data
+                             'sepal_length':':.2f', # customize hover for column of y attribute
+                             'petal_width':True, # add other column, default formatting
+                             'sepal_width':':.2f', # add other column, customized formatting
+                             # data not in dataframe, default formatting
+                             'suppl_1': (True, np.random.random(len(df))),
+                             # data not in dataframe, customized formatting
+                             'suppl_2': (':.3f', np.random.random(len(df)))
+                            })
+fig.update_layout(height=300)
+fig.show()
+```
+
 ### Customizing hover text with a hovertemplate
 
 To customize the tooltip on your graph you can use [hovertemplate](https://plotly.com/python/reference/#pie-hovertemplate), which is a template string used for rendering the information that appear on hoverbox.
diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 7ebf37547ac..e5b028c9e05 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -985,7 +985,7 @@ def build_dataframe(args, attrables, array_attrables):
                 bypass_warnings = (
                     hover_data_is_dict
                     and argument in args["hover_data"]
-                    and args["hover_data"][argument][1]
+                    and args["hover_data"][argument][1] is not None
                 )
                 if not df_provided and not bypass_warnings:
                     raise ValueError(
@@ -1022,7 +1022,7 @@ def build_dataframe(args, attrables, array_attrables):
                 if (
                     field_name == "hover_data"
                     and hover_data_is_dict
-                    and args["hover_data"][col_name][1]
+                    and args["hover_data"][col_name][1] is not None
                 ):
                     df_output[col_name] = args["hover_data"][col_name][1]
                 else:
diff --git a/packages/python/plotly/plotly/express/_doc.py b/packages/python/plotly/plotly/express/_doc.py
index b146b651eb7..d6f4007018e 100644
--- a/packages/python/plotly/plotly/express/_doc.py
+++ b/packages/python/plotly/plotly/express/_doc.py
@@ -185,7 +185,9 @@
         "or array_like objects",
         "or a dict with column names as keys, with values True (for default formatting)",
         "False (in order to remove this column from hover information),",
-        "or a formatting string, for example ':.3f' or '|%a'."
+        "or a formatting string, for example ':.3f' or '|%a'",
+        "or tuples with a bool or formatting string as first element,",
+        "and list-like data to appear in hover as second element",
         "Values from these columns appear as extra data in the hover tooltip.",
     ],
     custom_data=[
diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index 472644136b3..cd1fb52b626 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -20,7 +20,9 @@ def test_skip_hover():
 
 def test_composite_hover():
     df = px.data.tips()
-    hover_dict = OrderedDict({"day": False, "sex": True, "total_bill": ":.1f"})
+    hover_dict = OrderedDict(
+        {"day": False, "time": False, "sex": True, "total_bill": ":.1f"}
+    )
     fig = px.scatter(
         df,
         x="tip",
@@ -29,12 +31,11 @@ def test_composite_hover():
         facet_row="time",
         hover_data=hover_dict,
     )
-    assert (
-        fig.data[0].hovertemplate
-        == "time=Dinner<br>tip=%{x}<br>total_bill=%{customdata[2]:.1f}<br>sex=%{customdata[1]}<extra></extra>"
-        or fig.data[0].hovertemplate
-        == "time=Dinner<br>tip=%{x}<br>total_bill=%{customdata[1]:.1f}<br>sex=%{customdata[0]}<extra></extra>"
-    )
+    for el in ["tip", "total_bill", "sex"]:
+        assert el in fig.data[0].hovertemplate
+    for el in ["day", "time"]:
+        assert el not in fig.data[0].hovertemplate
+    assert ":.1f" in fig.data[0].hovertemplate
 
 
 def test_tuple_hover_data():
@@ -45,12 +46,38 @@ def test_tuple_hover_data():
         fig.data[0].hovertemplate
         == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]}<extra></extra>"
     )
-    fig = px.scatter(
-        x=[1, 2, 3],
-        y=[3, 4, 5],
-        hover_data={"comment": (":.1f", [1.234, 45.3455, 5666.234])},
-    )
-    assert (
-        fig.data[0].hovertemplate
-        == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]:.1f}<extra></extra>"
-    )
+    hover_dicts = [
+        {"comment": (":.1f", [1.234, 45.3455, 5666.234])},
+        {"comment": (":.1f", np.array([1.234, 45.3455, 5666.234]))},
+        {"comment": (":.1f", pd.Series([1.234, 45.3455, 5666.234]))},
+    ]
+    for hover_dict in hover_dicts:
+        fig = px.scatter(x=[1, 2, 3], y=[3, 4, 5], hover_data=hover_dict,)
+        assert (
+            fig.data[0].hovertemplate
+            == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]:.1f}<extra></extra>"
+        )
+
+
+def test_fail_wrong_column():
+    with pytest.raises(ValueError):
+        fig = px.scatter(
+            {"a": [1, 2], "b": [3, 4], "c": [2, 1]},
+            x="a",
+            y="b",
+            hover_data={"d": True},
+        )
+    with pytest.raises(ValueError):
+        fig = px.scatter(
+            {"a": [1, 2], "b": [3, 4], "c": [2, 1]},
+            x="a",
+            y="b",
+            hover_data={"d": ":.1f"},
+        )
+    with pytest.raises(ValueError):
+        fig = px.scatter(
+            {"a": [1, 2], "b": [3, 4], "c": [2, 1]},
+            x="a",
+            y="b",
+            hover_data={"d": (True, [3, 4, 5])},
+        )

From 7170a527430a041459b897e5916eb53c5db42c18 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Sun, 19 Apr 2020 23:20:34 +0200
Subject: [PATCH 14/20] address review comments

---
 doc/python/hover-text-and-formatting.md                    | 4 ++--
 packages/python/plotly/plotly/express/_core.py             | 6 ++++++
 packages/python/plotly/plotly/express/_doc.py              | 1 +
 .../plotly/plotly/tests/test_core/test_px/test_px_hover.py | 7 ++++++-
 4 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/doc/python/hover-text-and-formatting.md b/doc/python/hover-text-and-formatting.md
index 468dcced1d8..e47f1762822 100644
--- a/doc/python/hover-text-and-formatting.md
+++ b/doc/python/hover-text-and-formatting.md
@@ -124,7 +124,7 @@ fig.show()
 * `True` to add a different column, with default formatting
 * a formatting string starting with `:` for numbers [d3-format's syntax](https://github.com/d3/d3-3.x-api-reference/blob/master/Formatting.md#d3_forma), and `|` for dates in [d3-time-format's syntax](https://github.com/d3/d3-3.x-api-reference/blob/master/Time-Formatting.md#format), for example `:.3f`, `|%a`.
 
-For passing new data, the value is a tuple, which first element is one of the possible values described above for existing columns, and the second element correspond to the hover values, for example `(True, [1, 2, 3])` or `(':.1f', [1.54, 2.345])`.
+It is also possible to pass new data as values of the `hover_data` dict, either as list-like data, or inside a tuple, which first element is one of the possible values described above for existing columns, and the second element correspond to the list-like data, for example `(True, [1, 2, 3])` or `(':.1f', [1.54, 2.345])`.
 
 These different cases are illustrated in the following example.
 
@@ -138,7 +138,7 @@ fig = px.scatter(df, x='petal_length', y='sepal_length', facet_col='species', co
                              'petal_width':True, # add other column, default formatting
                              'sepal_width':':.2f', # add other column, customized formatting
                              # data not in dataframe, default formatting
-                             'suppl_1': (True, np.random.random(len(df))),
+                             'suppl_1': np.random.random(len(df)),
                              # data not in dataframe, customized formatting
                              'suppl_2': (':.3f', np.random.random(len(df)))
                             })
diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index e5b028c9e05..63981636add 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -885,6 +885,10 @@ def _get_reserved_col_names(args, attrables, array_attrables):
     return reserved_names
 
 
+def _isinstance_listlike(x):
+    return isinstance(x, list) or isinstance(x, np.ndarray) or isinstance(x, pd.Series)
+
+
 def build_dataframe(args, attrables, array_attrables):
     """
     Constructs a dataframe and modifies `args` in-place.
@@ -944,6 +948,8 @@ def build_dataframe(args, attrables, array_attrables):
     # If dict, convert all values of hover_data to tuples to simplify processing
     if hover_data_is_dict:
         for k in args["hover_data"]:
+            if _isinstance_listlike(args["hover_data"][k]):
+                args["hover_data"][k] = (True, args["hover_data"][k])
             if not isinstance(args["hover_data"][k], tuple):
                 args["hover_data"][k] = (args["hover_data"][k], None)
 
diff --git a/packages/python/plotly/plotly/express/_doc.py b/packages/python/plotly/plotly/express/_doc.py
index d6f4007018e..05a5b214cad 100644
--- a/packages/python/plotly/plotly/express/_doc.py
+++ b/packages/python/plotly/plotly/express/_doc.py
@@ -186,6 +186,7 @@
         "or a dict with column names as keys, with values True (for default formatting)",
         "False (in order to remove this column from hover information),",
         "or a formatting string, for example ':.3f' or '|%a'",
+        "or list-like data to appear in the hover tooltip",
         "or tuples with a bool or formatting string as first element,",
         "and list-like data to appear in hover as second element",
         "Values from these columns appear as extra data in the hover tooltip.",
diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index cd1fb52b626..c72b89cfa5e 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -38,7 +38,12 @@ def test_composite_hover():
     assert ":.1f" in fig.data[0].hovertemplate
 
 
-def test_tuple_hover_data():
+def test_newdatain_hover_data():
+    fig = px.scatter(x=[1, 2, 3], y=[3, 4, 5], hover_data={"comment": ["a", "b", "c"]})
+    assert (
+        fig.data[0].hovertemplate
+        == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]}<extra></extra>"
+    )
     fig = px.scatter(
         x=[1, 2, 3], y=[3, 4, 5], hover_data={"comment": (True, ["a", "b", "c"])}
     )

From f1ec098778f7f215a7a1f0e23de48740d81d4c82 Mon Sep 17 00:00:00 2001
From: Nicolas Kruchten <nicolas@plot.ly>
Date: Mon, 20 Apr 2020 09:30:57 -0400
Subject: [PATCH 15/20] short-circuit instead of bypass flag

---
 .../python/plotly/plotly/express/_core.py     | 30 +++++++++----------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 63981636add..72feb60f425 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -988,12 +988,17 @@ def build_dataframe(args, attrables, array_attrables):
             if isinstance(argument, str) or isinstance(
                 argument, int
             ):  # just a column name given as str or int
-                bypass_warnings = (
-                    hover_data_is_dict
-                    and argument in args["hover_data"]
-                    and args["hover_data"][argument][1] is not None
-                )
-                if not df_provided and not bypass_warnings:
+
+                if (
+                    field_name == "hover_data"
+                    and hover_data_is_dict
+                    and args["hover_data"][str(argument)][1] is not None
+                ):
+                    col_name = str(argument)
+                    df_output[col_name] = args["hover_data"][col_name][1]
+                    continue
+
+                if not df_provided:
                     raise ValueError(
                         "String or int arguments are only possible when a "
                         "DataFrame or an array is provided in the `data_frame` "
@@ -1001,7 +1006,7 @@ def build_dataframe(args, attrables, array_attrables):
                         "'%s' is of type str or int." % field
                     )
                 # Check validity of column name
-                if not bypass_warnings and argument not in df_input.columns:
+                if argument not in df_input.columns:
                     err_msg = (
                         "Value of '%s' is not the name of a column in 'data_frame'. "
                         "Expected one of %s but received: %s"
@@ -1012,7 +1017,7 @@ def build_dataframe(args, attrables, array_attrables):
                             "\n To use the index, pass it in directly as `df.index`."
                         )
                     raise ValueError(err_msg)
-                if not bypass_warnings and length and len(df_input[argument]) != length:
+                if length and len(df_input[argument]) != length:
                     raise ValueError(
                         "All arguments should have the same length. "
                         "The length of column argument `df[%s]` is %d, whereas the "
@@ -1025,14 +1030,7 @@ def build_dataframe(args, attrables, array_attrables):
                         )
                     )
                 col_name = str(argument)
-                if (
-                    field_name == "hover_data"
-                    and hover_data_is_dict
-                    and args["hover_data"][col_name][1] is not None
-                ):
-                    df_output[col_name] = args["hover_data"][col_name][1]
-                else:
-                    df_output[col_name] = df_input[argument].values
+                df_output[col_name] = df_input[argument].values
             # ----------------- argument is a column / array / list.... -------
             else:
                 is_index = isinstance(argument, pd.RangeIndex)

From a05679ef3178d0ae40f81316370bf3b1c3138383 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Tue, 21 Apr 2020 17:46:08 +0200
Subject: [PATCH 16/20] be more permissive when accepting data in hover dict

---
 .../python/plotly/plotly/express/_core.py     | 12 ++++++++++--
 .../tests/test_core/test_px/test_px_hover.py  | 19 ++++++++++++++-----
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 72feb60f425..97563273ea2 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -886,7 +886,15 @@ def _get_reserved_col_names(args, attrables, array_attrables):
 
 
 def _isinstance_listlike(x):
-    return isinstance(x, list) or isinstance(x, np.ndarray) or isinstance(x, pd.Series)
+    if (
+        isinstance(x, str)
+        or (isinstance(x, tuple) and len(x) == 2)
+        or isinstance(x, bool)
+        or x is None
+    ):
+        return False
+    else:
+        return True
 
 
 def build_dataframe(args, attrables, array_attrables):
@@ -952,7 +960,7 @@ def build_dataframe(args, attrables, array_attrables):
                 args["hover_data"][k] = (True, args["hover_data"][k])
             if not isinstance(args["hover_data"][k], tuple):
                 args["hover_data"][k] = (args["hover_data"][k], None)
-
+    print(args["hover_data"])
     # Loop over possible arguments
     for field_name in attrables:
         # Massaging variables
diff --git a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
index c72b89cfa5e..509f48d1991 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_px/test_px_hover.py
@@ -39,11 +39,19 @@ def test_composite_hover():
 
 
 def test_newdatain_hover_data():
-    fig = px.scatter(x=[1, 2, 3], y=[3, 4, 5], hover_data={"comment": ["a", "b", "c"]})
-    assert (
-        fig.data[0].hovertemplate
-        == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]}<extra></extra>"
-    )
+    hover_dicts = [
+        {"comment": ["a", "b", "c"]},
+        {"comment": (1.234, 45.3455, 5666.234)},
+        {"comment": [1.234, 45.3455, 5666.234]},
+        {"comment": np.array([1.234, 45.3455, 5666.234])},
+        {"comment": pd.Series([1.234, 45.3455, 5666.234])},
+    ]
+    for hover_dict in hover_dicts:
+        fig = px.scatter(x=[1, 2, 3], y=[3, 4, 5], hover_data=hover_dict)
+        assert (
+            fig.data[0].hovertemplate
+            == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]}<extra></extra>"
+        )
     fig = px.scatter(
         x=[1, 2, 3], y=[3, 4, 5], hover_data={"comment": (True, ["a", "b", "c"])}
     )
@@ -52,6 +60,7 @@ def test_newdatain_hover_data():
         == "x=%{x}<br>y=%{y}<br>comment=%{customdata[0]}<extra></extra>"
     )
     hover_dicts = [
+        {"comment": (":.1f", (1.234, 45.3455, 5666.234))},
         {"comment": (":.1f", [1.234, 45.3455, 5666.234])},
         {"comment": (":.1f", np.array([1.234, 45.3455, 5666.234]))},
         {"comment": (":.1f", pd.Series([1.234, 45.3455, 5666.234]))},

From b1c2cc3a90779f7b935d48d599042725d4320bc1 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Tue, 21 Apr 2020 17:52:16 +0200
Subject: [PATCH 17/20] remove print

---
 packages/python/plotly/plotly/express/_core.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 97563273ea2..0ccbe8d09f3 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -960,7 +960,6 @@ def build_dataframe(args, attrables, array_attrables):
                 args["hover_data"][k] = (True, args["hover_data"][k])
             if not isinstance(args["hover_data"][k], tuple):
                 args["hover_data"][k] = (args["hover_data"][k], None)
-    print(args["hover_data"])
     # Loop over possible arguments
     for field_name in attrables:
         # Massaging variables

From 6f1a148e82be141f6bc2f8a0ae67ea0749d98d19 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Tue, 21 Apr 2020 18:39:01 +0200
Subject: [PATCH 18/20] update tutorial

---
 doc/python/hover-text-and-formatting.md | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/doc/python/hover-text-and-formatting.md b/doc/python/hover-text-and-formatting.md
index 391cc0e415a..eb5957cb71a 100644
--- a/doc/python/hover-text-and-formatting.md
+++ b/doc/python/hover-text-and-formatting.md
@@ -169,13 +169,11 @@ fig.show()
 
 ### Customizing hover text with a hovertemplate
 
-To customize the tooltip on your graph you can use [hovertemplate](https://plotly.com/python/reference/#pie-hovertemplate), which is a template string used for rendering the information that appear on hoverbox.
+To customize the tooltip on your graph you can use the [hovertemplate](https://plotly.com/python/reference/#pie-hovertemplate) attribute of `graph_objects` tracces, which is a template string used for rendering the information that appear on hoverbox.
 This template string can include `variables` in %{variable} format, `numbers` in [d3-format's syntax](https://github.com/d3/d3-3.x-api-reference/blob/master/Formatting.md#d3_forma), and `date` in [d3-time-format's syntax](https://github.com/d3/d3-3.x-api-reference/blob/master/Time-Formatting.md#format).
 Hovertemplate customize the tooltip text vs. [texttemplate](https://plotly.com/python/reference/#pie-texttemplate) which customizes the text that appears on your chart. <br>
 Set the horizontal alignment of the text within tooltip with [hoverlabel.align](https://plotly.com/python/reference/#layout-hoverlabel-align).
 
-Plotly Express automatically sets the `hovertemplate`, but you can set it manually when using `graph_objects`.
-
 ```python
 import plotly.graph_objects as go
 
@@ -216,6 +214,24 @@ fig = go.Figure(go.Pie(
 fig.show()
 ```
 
+### Modifying the hovertemplate of a plotly express figure
+
+`plotly.express` automatically sets the hovertemplate but you can modify it using the `update_traces` method of the generated figure. It helps to print the hovertemplate generated by `plotly.express` in order to be able to modify it. One can also revert to the default hover information of traces by setting the hovertemplate to `None`.
+
+```python
+import plotly.express as px
+
+df_2007 = px.data.gapminder().query("year==2007")
+
+fig = px.scatter(df_2007, x="gdpPercap", y="lifeExp", log_x=True, color='continent'
+                )
+print("plotly express hovertemplate:", fig.data[0].hovertemplate)
+fig.update_traces(hovertemplate='GDP: %{x} <br>Life Expectany: %{y}') # 
+fig.update_traces(hovertemplate=None, selector={'name':'Europe'}) # revert to default hover
+print("user_defined hovertemplate:", fig.data[0].hovertemplate)
+fig.show()
+```
+
 ### Advanced Hover Template
 
 The following example shows how to format hover template. [Here](https://plotly.com/python/v3/hover-text-and-formatting/#dash-example) is an example to see how to format hovertemplate in Dash.

From 6fc67104d1a5e999ffb2e7a798762e20ffcccb53 Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Tue, 21 Apr 2020 21:33:15 +0200
Subject: [PATCH 19/20] add docstring to helper function

---
 packages/python/plotly/plotly/express/_core.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 0ccbe8d09f3..89b4ffce5e3 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -886,6 +886,10 @@ def _get_reserved_col_names(args, attrables, array_attrables):
 
 
 def _isinstance_listlike(x):
+    """Returns True if x is an iterable which can be transformed into a pandas Series,
+    False for the other types of possible values of a `hover_data` dict.
+    A tuple of length 2 is a special case corresponding to a (format, data) tuple.
+    """
     if (
         isinstance(x, str)
         or (isinstance(x, tuple) and len(x) == 2)

From 3c2a60775de7d1590392075ddb35555b292dca9d Mon Sep 17 00:00:00 2001
From: Emmanuelle Gouillart <emma@plot.ly>
Date: Tue, 21 Apr 2020 23:35:42 +0200
Subject: [PATCH 20/20] changelog

---
 CHANGELOG.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b2b05a9094f..ab4811baae3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,14 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## Dev version
+
+### Added
+
+- The `hover_data` parameter of `px` functions can now be a dictionary. This
+  makes it possible to skip hover information for some arguments or to change  
+  the formatting of hover informatiom [#2377](https://github.com/plotly/plotly.py/pull/2377).
+
 ## [4.6] - 2020-03-31
 
 ### Updated