# if a in list https://www.geeksforgeeks.org/check-if-element-exists-in-list-in-python/ 就是 你可以用 讓程式碼更簡潔。 ```python= for i in listA: if i in listB : return Ture ``` 去替代 ```python= for i in listA: for j in listB: if i==j : return Ture ```