Function restore

Lib/difflib.py:2073–2103

r""" Generate one of the two sequences that generated a delta. Given a `delta` produced by `Differ.compare()` or `ndiff()`, extract lines originating from file 1 or 2 (parameter `which`), stripping off line prefixes. Examples: >>> diff = ndiff('one\ntwo\nthree\n'.splitline

(delta, which)

def restore(delta, which):
    r"""
    Generate one of the two sequences that generated a delta.

    Given a `delta` produced by `Differ.compare()` or `ndiff()`, extract
    lines originating from file 1 or 2 (parameter `which`), stripping off line
    prefixes.

    Examples:

    >>> diff = ndiff('one\ntwo\nthree\n'.splitlines(keepends=True),
    ...              'ore\ntree\nemu\n'.splitlines(keepends=True))
    >>> diff = list(diff)
    >>> print(''.join(restore(diff, 1)), end="")
    one
    two
    three
    >>> print(''.join(restore(diff, 2)), end="")
    ore
    tree
    emu
    """
    try:
        tag = {1: "- ", 2: "+ "}[int(which)]
    except KeyError:
        raise ValueError('unknown delta choice (must be 1 or 2): %r'
                           % which) from None
    prefixes = ("  ", tag)
    for line in delta:
        if line[:2] in prefixes:
            yield line[2:]