A modern Fortran library for reading and writing CSV (comma-separated value) files.
git clone https://github.com/jacobwilliams/fortran-csv-module
cd fortran-csv-module
Build with fortran-lang/fpm
Fortran Package Manager (fpm) is a great package manager and build system for Fortran.
You can build using provided fpm.toml
:
fpm build
To use fortran-csv-module
within your fpm project, add the following to your fpm.toml
file:
[dependencies]
fortran-csv-module = { git="https://github.com/jacobwilliams/fortran-csv-module.git" }
Everything is handled by an object-oriented csv_file
class. Here is an example for writing a file:
program csv_write_test
use csv_module
use iso_fortran_env, only: wp => real64
implicit none
type(csv_file) :: f
logical :: status_ok
! set optional inputs:
call f%initialize(verbose = .true.)
! open the file
call f%open('test.csv',n_cols=4,status_ok=status_ok)
! add header
call f%add(['x','y','z','t'])
call f%next_row()
! add some data:
call f%add([1.0_wp,2.0_wp,3.0_wp],real_fmt='(F5.3)')
call f%add(.true.)
call f%next_row()
call f%add([4.0_wp,5.0_wp,6.0_wp],real_fmt='(F5.3)')
call f%add(.false.)
call f%next_row()
! finished
call f%close(status_ok)
end program csv_write_test
Which produces the following file:
x,y,z,t
1.000,2.000,3.000,T
4.000,5.000,6.000,F
Real, integer, logical, or character data can be added as scalars, vectors, and matrices.
When reading a CSV file, the data is stored internally in the class as allocatable character strings, which can be retrieved as real, integer, logical or character vectors as necessary. For example, to get the x
, y
, z
, and t
vectors from the previously-generated file:
program csv_read_test
use csv_module
use iso_fortran_env, only: wp => real64
implicit none
type(csv_file) :: f
character(len=30),dimension(:),allocatable :: header
real(wp),dimension(:),allocatable :: x,y,z
logical,dimension(:),allocatable :: t
logical :: status_ok
integer,dimension(:),allocatable :: itypes
! read the file
call f%read('test.csv',header_row=1,status_ok=status_ok)
! get the header and type info
call f%get_header(header,status_ok)
call f%variable_types(itypes,status_ok)
! get some data
call f%get(1,x,status_ok)
call f%get(2,y,status_ok)
call f%get(3,z,status_ok)
call f%get(4,t,status_ok)
! destroy the file
call f%destroy()
end program csv_read_test
Various options are user-selectable for specifying the format (e.g., changing the quote or delimiter characters). You can choose to enclose strings (or all fields) in quotes or not. The library works pretty well, and there are probably additional improvements that could be made. For one thing, it doesn't properly handle the case of a string that contains the delimiter character (I'll eventually fix this). If anybody has any other improvements, fork it and send me a pull request.
This library is released under a BSD-3 license.