将变量赋给数组

Question

我有以下行（注意：convert函数返回一个数组）：

question, answer = convert(snippet, phrase)

这是否会将数组中的前两个值分别分配给question和answer变量？

Answer 1

如果函数返回至少两个值的列表，则可以执行以下操作：

question, answer = convert(snippet, phrase)[:2]
#or 
question, answer, *_ = convert(snippet, phrase)

例如：

# valid multiple assignment/unpacking
x,y = 1, 2
x,y = [1,2,3][:2]
x,y, *z = [1, 2, 3, 4] # * -> put the rest as the list to z
x, y, *_z = [1, 2, 3, 4] # similar as above but, uses a 'throwaway' variable _

#invalid
x, y = 1, 2, 3 #ValueError: too many values to unpack (expected 2)

Answer 2

这在Python中被称为 unpacking 。

a, b, c = 1, 2, 3
# a -> 1
# b -> 2
# c -> 3