變量賦值給一個數組

Question

我有下面這行（注：轉換函數返回一個數組）：

question, answer = convert(snippet, phrase) 

這是否指定數組中的前兩個值分別question和answer變量？

Answer 1

如果函數返回至少兩個值的列表，你可以這樣做：

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

這在Python被稱爲unpacking。

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