while A and B: 同时满足A和B条件
while A or B：满足A或B任意一条
以1768. 交替合并字符串官方答案为启发，以前没意识到while还可以用and和or。
其实无论用什么，只要看最后的结果是True或False
class Solution:
def mergeAlternately(self, word1: str, word2: str) -> str:
m, n = len(word1), len(word2)
i = j = 0
ans = list()
while i < m or j < n:
if i < m:
ans.append(word1[i])
i += 1
if j < n:
ans.append(word2[j])
j += 1
return "".join(ans)
print(Solution().mergeAlternately(word1="abcd", word2="pq"))
标签：Python,word2,while,word1,str,ans From： https://www.cnblogs.com/daizichuan/p/17671449.html