lst = [j + k for j in s1 for k in s2]

或

lst = [(j, k) for j in s1 for k in s2]

如果你想要元组.

就像问题中一样，for j... 是外循环，for k... 是内循环.

Like in the question, for j... is the outer loop, for k... is the inner loop.

本质上，您可以在列表推导式中根据需要拥有任意数量的独立for x in y"子句，只需一个接一个地粘贴即可.

Essentially, you can have as many independent 'for x in y' clauses as you want in a list comprehension just by sticking one after the other.

为了使其更具可读性，请使用多行:

To make it more readable, use multiple lines:

lst = [
       j + k         # result
       for j in s1   # for loop 
         for k in s2 # for loop
                     # condition   
       ]