stdlib_array.md

title
array

The stdlib_array module

[TOC]

Introduction

Module for index manipulation and array handling tasks.

Derived types provided

array_wrapper_type

A derived type that wraps a polymorphic array_type and helps with its allocation. By loading an npz file with load_npz, a list of array wrappers will be obtained. On the other hand, a list of array wrappers can be saved to an npz file using save_npz. Use add_array to add an array to a list of array wrappers and call get_values on the array wrapper to obtain the values of the underlying array.

Status

Experimental

Example

program npz_example
    use stdlib_array, only: array_wrapper_type, add_array
    use stdlib_io_np, only: save_npz, load_npz
    implicit none

    type(array_wrapper_type), allocatable :: input_arrays(:), output_arrays(:)
    real :: x(3, 2) = 1
    integer :: y(2, 3) = 2
    real, allocatable :: x_out(:,:)
    integer, allocatable :: y_out(:,:)

    call add_array(input_arrays, x)
    call add_array(input_arrays, y)

    call save_npz('example_save.npz', input_arrays)

    call load_npz('example_save.npz', output_arrays)

    if (size(input_arrays) /= 2) then
        print *, 'Error: Output array has unexpected size.'; stop
    end if

    call output_arrays(1)%get_values(x_out)
    call output_arrays(2)%get_values(y_out)

    print *, x_out
    print *, y_out
end

array_type

An abstract type that can be extended according to the type and rank of the stored array. It is usually not necessary to interact with this type directly. It is used to store multiple arrays of different types and ranks in a single array.

Status

Experimental

Procedures and methods provided

trueloc

Status

Experimental

Description

Turn a logical mask into an index array by selecting all true values. Provides similar functionality like the built-in where or the intrinsic procedures merge and pack when working with logical mask. The built-in / intrinsics are usually preferable to trueloc, unless the access to the index array is required.

Syntax

loc = [[trueloc(function)]] (array[, lbound])

Class

Pure function.

Arguments

array: List of default logical arrays. This argument is intent(in).

lbound: Lower bound of the array to index. This argument is optional and intent(in).

Return value

Returns an array of default integer size, with a maximum length of size(array) elements.

Examples

{!example/array/example_trueloc.f90!}

falseloc

Status

Experimental

Description

Turn a logical mask into an index array by selecting all false values. Provides similar functionality like the built-in where or the intrinsic procedures merge and pack when working with logical mask. The built-in / intrinsics are usually preferable to falseloc, unless the access to the index array is required.

Syntax

loc = [[falseloc(function)]] (array[, lbound])

Class

Pure function.

Arguments

array: List of default logical arrays. This argument is intent(in).

lbound: Lower bound of the array to index. This argument is optional and intent(in).

Return value

Returns an array of default integer size, with a maximum length of size(array) elements.

Examples

{!example/array/example_falseloc.f90!}

add_array

Status

Experimental

Description

Add an array of defined type and rank to a list of array wrappers.

Syntax

call [[stdlib_array(module):add_array(interface)]] (arrays, array[, stat, msg, name])

Class

Pure subroutine.

Arguments

arrays: List of array wrappers of type array_wrapper_type to add array to. This argument is intent(inout).

array: Array with defined type and rank to be added to the list of array wrappers. This argument is intent(in).

stat: Status variable of type integer. This argument is optional and intent(out). The operation is successful if stat is 0.

msg: Error message. This argument is optional and intent(out).

name: Name of the array. This argument is optional and intent(in). If not provided, the name will be set to the default value.

Examples

{!example/io/example_save_npz.f90!}

get_values

Status

Experimental

Description

Get the values of the array within the array wrapper.

Syntax

call [[stdlib_array(module):array_wrapper_type(type)]] % [[array_wrapper_type(type):get_values(bound)]] (wrapper, values[, stat, msg])

Class

Pure subroutine.

Arguments

wrapper: Array wrapper of type array_wrapper_type to get the values from. This argument is intent(in).

values: Array of the same type and rank as the array within the array wrapper. This argument is intent(out).

stat: Status variable of type integer. This argument is optional and intent(out). The operation is successful if stat is 0.

msg: Error message. This argument is optional and intent(out).

Examples

{!example/io/example_load_npz.f90!}