pyextend库-unpack列表集合字符串解包函数

Posted 2020-06-14

pyextend - python extend lib

unpack (iterable, count, fill=None)

参数:

iterable: 实现 __iter__的可迭代对象, 如 str, tuple, dict, list

count:    需要拆分的数量, 如数值大于 len(iterable) 则使用 fill 的值进行后续填充

fill:          默认值填充

使用范例:

Example 1:
        In[1]: source = ‘abc‘
        In[2]: a, b = unpack(source, 2)
        In[3]: print(a, b)
        a b

Example 2:
        In[1]: source = ‘abc‘
        In[2]: a, b, c, d = unpack(source, 4)
        In[3]: print(a, b, c, d)
        a b None None

 

代码:

@accepts(iterable=‘__iter__‘, count=int)
def unpack(iterable, count, fill=None):
    """
    The iter data unpack function.

    """
    iterable = list(enumerate(iterable))
    cnt = count if count <= len(iterable) else len(iterable)
    results = [iterable[i][1] for i in range(cnt)]

    # results[len(results):len(results)] = [fill for i in range(count-cnt)]
    results = merge(results, [fill for i in range(count-cnt)])
    return tuple(results)