algs.py 文件源码

def add_at_idx(t, idx, val, typ=tuple, op=operator.__add__):
    """
    add_at_idx(t, idx, val, typ=tuple, op=operator.__add__) ->
        t with t[idx] = op(t[idx], val)
    """
    return t[:idx] + typ((op(t[idx], val),)) + t[idx+1:]