stdlib_io.md

title
io

IO

[TOC]

loadtxt - load a 2D array from a text file

Status

Experimental

Description

Loads a rank-2 array from a text file.

Syntax

call [[stdlib_io(module):loadtxt(interface)]] (filename, array [, skiprows] [, max_rows] [, fmt])

Arguments

filename: Shall be a character expression containing the file name from which to load the rank-2 array.

array: Shall be an allocatable rank-2 array of type real, complex or integer.

skiprows (optional): Skip the first skiprows lines. If skipping more rows than present, a 0-sized array will be returned. The default is 0.

max_rows (optional): Read max_rows lines of content after skiprows lines. A negative value results in reading all lines. A value of zero results in no lines to be read. The default value is -1.

fmt (optional): Fortran format specifier for the text read. Defaults to the write format for the data type. Setting fmt='*' will specify list directed read.

Return value

Returns an allocated rank-2 array with the content of filename.

Example

{!example/io/example_loadtxt.f90!}

open - open a file

Status

Experimental

Description

Returns the unit number of a file opened to read, to write, or to read and write. The file might be a text file or a binary file. All files are opened using a streamed access.

Syntax

u = [[stdlib_io(module):open(function)]] (filename [, mode] [, iostat])

Arguments

filename: Shall be a character expression containing the name of the file to open.

mode (optional): Shall be a character expression containing characters describing the way in which the file will be used. The available modes are:

Character	Meaning
'r'	open for reading (default)
'w'	open for writing, truncating the file first
'x'	open for exclusive creation, failing if the file already exists
'a'	open for writing, appending to the end of the file if it exists
'+'	open for updating (reading and writing)
'b'	binary mode
't'	text mode (default)

The default mode is 'rt' (i.e. open for reading a text file). The mode may include one of the four different methods for opening a file (i.e., 'r', 'w', 'x', and 'a'). These four methods can be associated with the character '+' to open the file for updating. In addition, it can be specified if the file should be handled as a binary file ('b') or a text file ('t').

iostat (optional): Shall be a scalar of type integer that receives the error status of open, if provided. If no error exists, iostat is zero.

u: Shall be a scalar of type integer that specifies the unit number associated with the file filename.

Return value

The result is a scalar of type integer.

Example

{!example/io/example_open.f90!}

savetxt - save a 2D array into a text file

Status

Experimental

Description

Saves a rank-2 array into a text file.

Syntax

call [[stdlib_io(module):savetxt(interface)]] (filename, array)

Arguments

filename: Shall be a character expression containing the name of the file that will contain the 2D array.

array: Shall be a rank-2 array of type real, complex or integer.

Output

Provides a text file called filename that contains the rank-2 array.

Example

{!example/io/example_savetxt.f90!}

load_npy

Status

Experimental

Description

Loads an array from a npy formatted binary file.

Syntax

call [[stdlib_io_npy(module):load_npy(interface)]] (filename, array[, iostat][, iomsg])

Arguments

filename: Shall be a character expression containing the file name from which to load the array. This argument is intent(in).

array: Shall be an allocatable array of any rank of type real, complex or integer. This argument is intent(out).

iostat: Default integer, contains status of loading to file, zero in case of success. It is an optional argument, in case not present the program will halt for non-zero status. This argument is intent(out).

iomsg: Deferred length character value, contains error message in case iostat is non-zero. It is an optional argument, error message will be dropped if not present. This argument is intent(out).

Return value

Returns an allocated array with the content of filename in case of success.

Example

{!example/io/example_loadnpy.f90!}

save_npy

Status

Experimental

Description

Saves an array into a npy formatted binary file.

Syntax

call [[stdlib_io_npy(module):save_npy(interface)]] (filename, array[, iostat][, iomsg])

Arguments

filename: Shall be a character expression containing the name of the file that will contain the array. This argument is intent(in).

array: Shall be an array of any rank of type real, complex or integer. This argument is intent(in).

iostat: Default integer, contains status of saving to file, zero in case of success. It is an optional argument, in case not present the program will halt for non-zero status. This argument is intent(out).

iomsg: Deferred length character value, contains error message in case iostat is non-zero. It is an optional argument, error message will be dropped if not present. This argument is intent(out).

Output

Provides a npy file called filename that contains the rank-2 array.

Example

{!example/io/example_savenpy.f90!}

get_line

Status

Experimental

Description

Read a whole line from a formatted unit into a string variable

Syntax

call [[stdlib_io(module):get_line(interface)]] (unit, line[, iostat][, iomsg])

call [[stdlib_io(module):get_line(interface)]] (line[, iostat][, iomsg])

Arguments

unit: Formatted input unit. This argument is intent(in). If unit is not specified standard input is used.

line: Deferred length character or string_type variable. This argument is intent(out).

iostat: Default integer, contains status of reading from unit, zero in case of success. It is an optional argument, in case not present the program will halt for non-zero status. This argument is intent(out).

iomsg: Deferred length character value, contains error message in case iostat is non-zero. It is an optional argument, error message will be dropped if not present. This argument is intent(out).

Example

{!example/io/example_get_line.f90!}

Formatting constants

Status

Experimental

Description

Formatting constants for printing out integer, floating point, and complex numbers at their full precision. Provides formats for all kinds as defined in the stdlib_kinds module.

Example

{!example/io/example_fmt_constants.f90!}

get_file - Read a whole ASCII file into a character or a string variable

Status

Experimental

Description

This subroutine interface reads the entirety of a specified ASCII file and returns its content as a string or an allocatable character variable. The function provides an optional error-handling mechanism via the state_type class. If the err argument is not provided, exceptions will trigger an error stop. The function also supports an optional flag to delete the file after reading.

Syntax

call [[stdlib_io(module):get_file(subroutine)]] (filename, file [, err] [, delete=.false.])

Class

Function

Arguments

filename: Shall be a character input containing the path to the ASCII file to read. It is an intent(in) argument.

file: Shall be a type(string_type) or an allocatable character variable containing the full content of the specified file. It is an intent(out) argument.

err (optional): Shall be a type(state_type) variable. It is an intent(out) argument used for error handling.

delete (optional): Shall be a logical flag. If .true., the file is deleted after reading. Default is .false.. It is an intent(in) argument.

Return values

Output variable file will contain the full content of the specified file.

Raises STDLIB_IO_ERROR if the file is not found, cannot be opened, read, or deleted. Exceptions trigger an error stop unless the optional err argument is provided.

Example

{!example/io/example_get_file.f90!}