py3-world-files-test

world-files.py

import os

def world_files(fname):
    """
    Determine potential world filename combinations, without checking
    their existence.

    For example, a '*.tif' file may have one of the following
    popular conventions for world file extensions '*.tifw',
    '*.tfw', '*.TIFW' or '*.TFW'.

    Given the possible world file extensions, the upper case basename
    combinations are also generated. For example, the file 'map.tif'
    will generate the following world file variations, 'map.tifw',
    'map.tfw', 'map.TIFW', 'map.TFW', 'MAP.tifw', 'MAP.tfw', 'MAP.TIFW'
    and 'MAP.TFW'.

    Args:

    * fname:
        Name of the file for which to get all the possible world
        filename combinations.

    Returns:
        A list of possible world filename combinations.

    Examples:

    >>> from cartopy.io.img_nest import Img
    >>> Img.world_files('img.png')[:6]
    ['img.pngw', 'img.pgw', 'img.PNGW', 'img.PGW', 'IMG.pngw', 'IMG.pgw']
    >>> Img.world_files('/path/to/img.TIF')[:2]
    ['/path/to/img.tifw', '/path/to/img.tfw']
    >>> Img.world_files('/path/to/img/with_no_extension')[0]
    '/path/to/img/with_no_extension.w'

    """
    froot, fext = os.path.splitext(fname)
    # If there was no extension to the filename.
    if froot == fname:
        result = ['{}.{}'.format(fname, 'w'),
                  '{}.{}'.format(fname, 'W')]
    else:
        fext = fext[1::].lower()
        if len(fext) < 3:
            result = ['{}.{}'.format(fname, 'w'),
                      '{}.{}'.format(fname, 'W')]
        else:
            fext_types = [fext + 'w', fext[0] + fext[-1] + 'w']
            fext_types.extend([ext.upper() for ext in fext_types])
            result = ['{}.{}'.format(froot, ext) for ext in fext_types]

    def _convert_basename(name):
        dirname, basename = os.path.dirname(name), os.path.basename(name)
        base, ext = os.path.splitext(basename)
        if base == base.upper():
            result = base.lower() + ext
        else:
            result = base.upper() + ext
        if dirname:
            result = os.path.join(dirname, result)
        return result

    # result.extend(map(_convert_basename, result))           # original
    # result += [_convert_basename(r) for r in result]        # PR #448
    # result.extend(_convert_basename(r) for r in result)     # generator expression
    result.extend([_convert_basename(r) for r in result])     # list comprehension
    return result

world_files("img.png")