io

IO

loadtxt - load a 2D array from a text file

Status

Experimental

Description

Loads a rank-2 array from a text file.

Syntax

call loadtxt (filename, array [, skiprows] [, max_rows])

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.

Return value

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

Example

program example_loadtxt
  use stdlib_io, only: loadtxt
  implicit none
  real, allocatable :: x(:, :)
  call loadtxt('example.dat', x)
end program example_loadtxt

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 = open (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

program example_open
  use stdlib_io, only: open
  implicit none
  integer :: u
  u = open ('example.dat', 'wt')
  write (u, '(a)') 'This is an example for open'
  close (u)
end program example_open

savetxt - save a 2D array into a text file

Status

Experimental

Description

Saves a rank-2 array into a text file.

Syntax

call savetxt (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

program example_savetxt
  use stdlib_io, only: savetxt
  implicit none
  real :: x(3, 2) = 1
  call savetxt('example.dat', x)
end program example_savetxt

load_npy

Status

Experimental

Description

Loads an array from a npy formatted binary file.

Syntax

call load_npy (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

program example_loadnpy
  use stdlib_io_npy, only: load_npy
  implicit none
  real, allocatable :: x(:, :)
  call load_npy('example.npy', x)
end program example_loadnpy

save_npy

Status

Experimental

Description

Saves an array into a npy formatted binary file.

Syntax

call save_npy (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

program example_savenpy
  use stdlib_io_npy, only: save_npy
  implicit none
  real :: x(3, 2) = 1
  call save_npy('example.npy', x)
end program example_savenpy

getline

Status

Experimental

Description

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

Syntax

call getline (unit, line[, iostat][, iomsg])

call getline (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

program example_getline
  use, intrinsic :: iso_fortran_env, only: input_unit, output_unit
  use stdlib_io, only: getline
  implicit none
  character(len=:), allocatable :: line
  integer :: stat

  call getline(input_unit, line, stat)
  do while (stat == 0)
    write (output_unit, '(a)') line
    call getline(input_unit, line, stat)
  end do
end program example_getline

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

program example_fmt_constants
  use stdlib_kinds, only: int32, int64, sp, dp
  use stdlib_io, only: FMT_INT, FMT_REAL_SP, FMT_REAL_DP, FMT_COMPLEX_SP, FMT_COMPLEX_DP
  implicit none

  integer(kind=int32) :: i32
  integer(kind=int64) :: i64
  real(kind=sp)       :: r32
  real(kind=dp)       :: r64
  complex(kind=sp)    :: c32
  complex(kind=dp)    :: c64

  i32 = 100_int32
  i64 = 100_int64
  r32 = 100.0_sp
  r64 = 100.0_dp
  c32 = cmplx(100.0_sp, kind=sp)
  c64 = cmplx(100.0_dp, kind=dp)

  print "(2("//FMT_INT//",1x))", i32, i64 ! outputs: 100 100
  print FMT_REAL_SP, r32                  ! outputs: 1.00000000E+02
  print FMT_REAL_DP, r64                  ! outputs: 1.0000000000000000E+002
  print FMT_COMPLEX_SP, c32               ! outputs: 1.00000000E+02  0.00000000E+00
  print FMT_COMPLEX_DP, c64               ! outputs: 1.0000000000000000E+002  0.0000000000000000E+000

end program example_fmt_constants