utils.py 文件源码

def match(v1, v2, nomatch=-1, incomparables=None, start=0):
    """
    Return a vector of the positions of (first)
    matches of its first argument in its second.

    Parameters
    ----------
    v1: array-like
        the values to be matched

    v2: array-like
        the values to be matched against

    nomatch: int
        the value to be returned in the case when
        no match is found.

    incomparables: array-like
        a list of values that cannot be matched.
        Any value in v1 matching a value in this list
        is assigned the nomatch value.
    start: int
        type of indexing to use. Most likely 0 or 1
    """
    lookup = {}
    for i, x in enumerate(v2):
        if x not in lookup:
            lookup[x] = i

    lst = [nomatch] * len(v1)
    skip = set(incomparables) if incomparables else set()
    for i, x in enumerate(v1):
        if x in skip:
            continue

        with suppress(KeyError):
            lst[i] = lookup[x] + start

    return lst