Mapytex/pymath/calculus/decorators.py

#!/usr/bin/env python
# encoding: utf-8

from functools import wraps

def no_repetition(equals=lambda x,y: x == y, old = ""):
    """ Remove yield values which has already been yield

    :param equals: test for equality
    :param old: initiate form of data.
    :returns: same generator with no repetitions

    >>> norep = no_repetition()
    >>> def str_gene(string):
    ...    for i in string:
    ...        yield i
    >>> norep_str_gene = norep(str_gene)
    >>> [i for i in norep_str_gene("aaabraabbbere")]
    ['a', 'b', 'r', 'a', 'b', 'e', 'r', 'e']

    """
    def wrapper(fun):
        @wraps(fun)
        def dont_repeat(*args, **kwrds):
            gen = fun(*args, **kwrds)
            old_s = old
            while True:
                try:
                    new_s = next(gen)
                except StopIteration:
                    break
                else:
                    if not equals(new_s, old_s):
                        old_s = new_s
                        yield new_s

        return dont_repeat
    return wrapper



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