iter_utils.py 文件源码

def peek(iterable):
    """  
    Peek ahead in an iterable. 

    Parameters
    ----------
    iterable : iterable

    Returns
    -------
    first : object
        First element of ``iterable``
    stream : iterable
        Iterable containing ``first`` and all other elements from ``iterable``
    """
    iterable = iter(iterable)
    ahead = next(iterable)
    return ahead, chain([ahead], iterable)