list 查 --in --not in --count --index 运用

li = ['alex','wusir','ritian','barry','wenzhou']
re = 'alex' in li
print(re)
#  True
li = ['alex','wusir','ritian','barry','wenzhou']
re = 'alex' not in li
print(re)
#  False
li = ['alex','wusir','ritian','barry','wenzhou']
re = li.count('r')
print(re)
#   0
li = ['alex','wusir','ritian','barry','wenzhou']
re = li.count('alex')
print(re)
#  1
li = ['alex','wusir','ritian','barry','wenzhou']
re = li.index('alex')
print(re)
#  0
li = ['alex','wusir','ritian','barry','wenzhou']
re = li.index('wusir',0,6)
print(re)
#  1
li = ['alex','wusir','ritian','barry','wenzhou']
re = li.index('wusir',2,6)
print(re)
#  ValueError: 'wusir' is not in list

in、not in、count、index；

下面以  List = ["L","rong","wu","forever"]  为例

（1）in字符 ：判断值是否在列表中

（2）not in字符 ：判断值是否不再列表中

（3）count字符 ：统计指定值在列表中出现的次数

（4）index字符 ：查看指定值在列表中出现的次数