【Python】Python中in與not in

在python中，要判斷特定的值是否存在列表中，可使用關鍵字in,判斷特定的值不存在列表中，可使用關鍵字not in

letters = ['A','B','C','D','E','F','G']
if 'A' in letters:
    print('A'+' exists')
if 'h' not in letters:
    print('h'+' not exists')

打印結果：

A exists
h not exists

一個稍微復雜的案例

定義2個列表分別為list_01跟list_02

list_01 = ['A','B','C','H']
list_02 = ['A','B','E','F']

通過判斷查看list_01在list_02中的存在情況

list_01 = ['A','B','C','H']
list_02 = ['A','B','E','F']

for letter in list_01:
    if letter in list_02:
        print(letter+' is exists')
    else:
        print(letter+' is not exists')

打印結果：

A is exists
B is exists
C is not exists
H is not exists