imcflibs.strtools

  1"""String related helper functions."""
  2
  3import re
  4
  5
  6# this is taken from numpy's iotools:
  7def _is_string_like(obj):
  8    """Check whether obj behaves like a string.
  9
 10    Using this way of checking for a string-like object is more robust when
 11    dealing with stuff that can behave like a 'str' but is not strictly an
 12    instance of it (or a subclass thereof). So it's more generic than using
 13    isinstance(obj, str).
 14
 15    Example
 16    -------
 17    >>> _is_string_like('foo')
 18    True
 19    >>> _is_string_like(123)
 20    False
 21    """
 22    try:
 23        obj + ""
 24    except (TypeError, ValueError):
 25        return False
 26    return True
 27
 28
 29def filename(name):
 30    """Get the filename from either a filehandle or a string.
 31
 32    This is a convenience function to retrieve the filename as a string given
 33    either an open filehandle or just a plain str containing the name.
 34
 35    When running in Jython the function will also convert `java.io.File` objects
 36    to `str`. NOTE: this also works if the Java object is a directory, not an
 37    actual file.
 38
 39    Parameters
 40    ----------
 41    name : str or filehandle or java.io.File
 42
 43    Returns
 44    -------
 45    name : str
 46
 47    Example
 48    -------
 49    >>> filename('test_file_name')
 50    'test_file_name'
 51
 52    >>> import os.path
 53    >>> fname = filename(open(__file__, 'r'))
 54    >>> os.path.basename(fname) in ['strtools.py', 'strtools.pyc']
 55    True
 56    """
 57    try:
 58        if isinstance(name, java.io.File):
 59            return str(name)
 60    except:
 61        # we silently ignore this case and continue with checks below as most
 62        # likely we are not running under Jython
 63        pass
 64
 65    if isinstance(name, file):
 66        return name.name
 67    elif _is_string_like(name):
 68        return name
 69    else:
 70        raise TypeError
 71
 72
 73def flatten(lst):
 74    """Make a single string from a list of strings.
 75
 76    Parameters
 77    ----------
 78    lst : list(str)
 79
 80    Returns
 81    -------
 82    flat : str
 83
 84    Example
 85    -------
 86    >>> flatten(('foo', 'bar'))
 87    'foobar'
 88    """
 89    flat = ""
 90    for line in lst:
 91        flat += line
 92    return flat
 93
 94
 95def strip_prefix(string, prefix):
 96    """Remove a given prefix from a string.
 97
 98    Parameters
 99    ----------
100    string : str
101        The original string from which the prefix should be removed.
102    prefix : str
103        The prefix to be removed.
104
105    Returns
106    -------
107    str
108        The original string without the given prefix. In case the original
109        string doesn't start with the prefix, it is returned unchanged.
110    """
111    if string.startswith(prefix):
112        string = string[len(prefix) :]
113    return string
114
115
116def sort_alphanumerically(data):
117    """Sort a list alphanumerically.
118
119    Parameters
120    ----------
121    data : list
122        List containing all the files to sort.
123
124    Returns
125    -------
126    list
127        List with filenames sorted.
128
129    Examples
130    --------
131    >>> sorted([ "foo-1", "foo-2", "foo-10" ])
132    ["foo-1", "foo-10", "foo-2"]
133
134    >>> sort_alphanumerically([ "foo-1", "foo-2", "foo-10" ])
135    ["foo-1", "foo-2", "foo-10"]
136    """
137    convert = lambda text: int(text) if text.isdigit() else text.lower()
138    alphanum_key = lambda key: [convert(c) for c in re.split("([0-9]+)", key)]
139    return sorted(data, key=alphanum_key)