Forlab Wiki Home

Welcome to the forlab wiki!

Examples & Help Documents

File interaction method

Description

In addition to pre-compiled code, our program may also need to interact with files. Forlab sets up ASCII text file, binary file read and write functions, which are implemented in forlab_save.fypp, forlab_load.fypp and forlab_file.fypp. We can perform data interaction from regularized ASCII text files and binary files. Generally, in order to avoid eof errors, we need to obtain some basic information of the file when interacting with the file, such as whether the file exists, file name, file size, and file storage format.

Query the number of file lines

countlines returns the number of lines in the file.

filelines = countlines('ASCII.txt')
    !! Directly query the number of file('ASCII.txt') lines
---
infile = file(filename)
    !! Initialization file
filelines = infile%countlines()

[file] \todo

Check if the file exists

Similar to querying the number of file lines, file_exist queries whether the file exists.

ok = file_exist('ASCII.txt')
    !! Directly query the number of file('ASCII.txt') lines
---
infile = file(filename)
    !! Initialization file
ok = infile%exist()

ForLab file operations

We hide the direct specification of the unit number and leave it to the compiler to specify, we can access the file unit number through infile%unit.
Type file contains two data: file%unit, file%filename.

type(file) :: infile
infile = file(filename)
    !! Initialization file
call infile%open('r')
ok = infile%exist()
filelines = infile%countlines()
call infile%close()

Save/Load methods

ASCII files

It is difficult to realize that the fortran return value is polymorphic. We choose to use subroutines.

call savetxt(filename, x)
    !! Store the data of x in filename, the maximum dimension of x is 2 dimensions
call loadtxt(filename, x)
    !! Read data from file

Binary file

Similar to the ASCII file reading and writing method.

call savebin(filename, x)
    !! Store the data of x in filename, the maximum dimension of x is 3 dimensions
call loadbin(filename, x)
    !! Read data from file

If you need more complex requirements, please use the open source hdf5 and netcdf packages.