old_contents: #coding=utf8
  
  while True:
  	A = input('Please input the first list:')
  	B = input('Please input the first list:')
  	L=[]
  	[L.append(s1[a]+s2[b]) for a in A for b in B]
  	print(L)
  
new_contents: #coding=utf8
  
  while True:
  	A = input('Please input the first list:')
  	B = input('Please input the first list:')
  	print( [int(a)+int(b) for a in A.split() for b in B.split()] )
  
subject: 添加2.py(列表解析的双重循环)