functions.py 文件源码

def create_map(*cols):
    """Creates a new map column.

    :param cols: list of column names (string) or list of :class:`Column` expressions that grouped
        as key-value pairs, e.g. (key1, value1, key2, value2, ...).

    >>> df.select(create_map('name', 'age').alias("map")).collect()
    [Row(map={u'Alice': 2}), Row(map={u'Bob': 5})]
    >>> df.select(create_map([df.name, df.age]).alias("map")).collect()
    [Row(map={u'Alice': 2}), Row(map={u'Bob': 5})]
    """
    sc = SparkContext._active_spark_context
    if len(cols) == 1 and isinstance(cols[0], (list, set)):
        cols = cols[0]
    jc = sc._jvm.functions.map(_to_seq(sc, cols, _to_java_column))
    return Column(jc)