Question

I have two utility functions that either append or remove a pattern onto a set of items within a directory. The functionality is exactly the same apart from the line that does the renaming which makes me believe I can merge them into one function.

Here are the two functions:

def append_items(source, pattern, dirs = True, recurse = False):
    """
    Append the pattern to all items within a directory

    source = act on this directory
    pattern = add this to the start of the file
    dirs = apply to directorys
    recurse = work recursively 
    """
    for item in os.listdir(source):
        path =  os.path.join(source, item)
        if "svn" not in item:
            if os.path.isdir(path):
                # Recurse first
                if recurse:
                    append_items(path, pattern, dirs, recurse)
                if dirs:
                    rename(path, path + pattern)
            elif os.path.isfile(path):
                name, ext = os.path.splitext(item)
                # Append pattern, add extension back
                new_path = os.path.join(source, "%s%s" % (name, pattern) + ext)
                rename(path, new_path)

#----------------------------------------------------------------------------------------------------------

def remove_string_from_items(source, pattern, dirs = True, recurse = False):
    """
    Remove a pattern from all items within a directory

    source =  directory
    pattern = text to replace
    """
    for item in os.listdir(source):
        path =  os.path.join(source, item)
        if "svn" not in item:
            if os.path.isdir(path):
                # Recurse first
                if recurse:
                    remove_string_from_items(path, pattern, dirs, recurse)
                if dirs and pattern in item:
                    target = os.path.join(source, string.replace(item, pattern, ""))
                    rename(path, target)
            elif os.path.isfile(path) and pattern in item:
                target = os.path.join(source, string.replace(item, pattern, ""))
                rename(path, target)

Can anybody point me towards a cleaner solution?

Answer 1

The following should be equivalent to what you have, with less repeated code:

def _append_or_remove(source, pattern, dirs = True, recurse = False, append = True):
    for item in os.listdir(source):
        path =  os.path.join(source, item)
        if "svn" not in item:
            if os.path.isdir(path):
                # Recurse first
                if recurse:
                    if append:
                        append_items(path, pattern, dirs, recurse)
                    else:
                        remove_string_from_items(path, pattern, dirs, recurse)
                if dirs and pattern in item:
                    target = os.path.join(source, string.replace(item, pattern, ""))
                    rename(path, target)
            elif os.path.isfile(path) and pattern in item:
                if append:
                    name, ext = os.path.splitext(item)
                    # Append pattern, add extension back
                    target = os.path.join(source, "%s%s" % (name, pattern) + ext)
                else:
                    target = os.path.join(source, string.replace(item, pattern, ""))
                rename(path, target)

def append_items(source, pattern, dirs = True, recurse = False):
    """
    Append the pattern to all items within a directory

    source = act on this directory
    pattern = add this to the start of the file
    dirs = apply to directorys
    recurse = work recursively 
    """
    return _append_or_remove(source, pattern, dirs, recurse, True)

def remove_string_from_items(source, pattern, dirs = True, recurse = False):
    """
    Remove a pattern from all items within a directory

    source =  directory
    pattern = text to replace
    """
    return _append_or_remove(source, pattern, dirs, recurse, False)