flibs/strings(n) 1.0 "flibs"

NAME

flibs/strings - Writing CSV files

    TABLE OF CONTENTS
    SYNOPSIS
    DESCRIPTION
    ROUTINES
    COPYRIGHT

SYNOPSIS

use csv_file

call csv_next_record( lun )

call csv_write( lun, data )

DESCRIPTION

The csv_file module facilitates the writing of CSV files. Whereas it is very easy to read CSV files with Fortran, using list-directed read statements:

integer :: i1, i2 character(len=20) :: string real :: f3 read(10,*) i1, i2, string, f3

for instance, writing them is slightly more complicated. The module helps with this by two routines, csv_next_record and csv_write.

The module supports writing scalar variables, one- and two-dimensional arrays according to a simple scheme. As CSV files are ordinary formatted files where each field is separated by commas and strings are possibly delimited by quotation marks ("), the procedure is this:

Open the file as a formatted file
Pass the LU-number for the file to the routines mentioned above, using the second to write the data and the first to force a new record.

In more detail, the layout of the CSV-file can be described as follows:

Single items are written to the end of the current record
One-dimensional items are also written to the end of the current record
Two-dimensional items are written to separate records, one for each row
Except for the two-dimensional versions, all routines allow you to suppress advancing to the next record:
- for single items you must indicate whether to advance or not
- for one-dimensional items, the argument is optional. Default is to advance.

Note on the format: CSV-files apparently come in different guises (Kernighan and Pike, The practice of Programming, Addison-Wesley, 1999). This module uses the following rules:

items are always separated by a single comma (,)
string items are delimited by double quotes (")
embedded double quotes are treated by doubling the quote
trailing blanks are considered irrelevant

ROUTINES

The module contains two public subroutines:

use csv_file

To import the subroutines for writing a CSV file, use this module.

call csv_next_record( lun )

Writes a new line to the file.

integer lun: The LU-number the file is connected to

call csv_write( lun, data )

Writes data to the file in the proper format.

integer lun

The LU-number the file is connected to

(...) data

The data to be written to the file. The type can be:

an integer or a real (single or double precision) number or a character string
an integer or a real (single or double precision)one-dimensional array or a one-dimensional array of character strings
an integer or a real (single or double precision)two-dimensional array or a two-dimensional array of character strings