字符串操作
以下字符串可以 变量.函数() 也可以 "字符串".函数()
capitalize()
首字母大写，其余转换为小写
print("test TEST".capitalize())
输出
C:\Users\Administrator\AppData\Local\Programs\Python\Python37\python.exe D:/Python/Day02/test.py
Test test
Process finished with exit code 0
count()
count("str")，统计字符串出现的次数，跟列表的用法一样
print("test test".count("t"))
输出
C:\Users\Administrator\AppData\Local\Programs\Python\Python37\python.exe D:/Python/Day02/test.py 4 Process finished with exit code 0
center()
center(number,"str") 让内容显示在中间，使内容两侧填充字符串，默认是空格
print("test".center(50,"-"))
输出
C:\Users\Administrator\AppData\Local\Programs\Python\Python37\python.exe D:/Python/Day02/test.py -----------------------test----------------------- Process finished with exit code 0
endswith()
endswith("str")，判断字符串结尾是否包含 “str“，是则True 否则False
print("i am shuaige".endswith("ge"))
输出
C:\Users\Administrator\AppData\Local\Programs\Python\Python37\python.exe D:/Python/Day02/test.py
True
Process finished with exit code 0
find()
find("str") 查找字符串并返回索引值，如果不存在则返回 -1
print("i am shuaige".find("am"))
输出
C:\Users\Administrator\AppData\Local\Programs\Python\Python37\python.exe D:/Python/Day02/test.py 2 Process finished with exit code 0
format_map()
和format用法一样，字符格式化。只是格式不一样
print("my name is {name} i am {age} years old".format_map({"name":"DaHua","age":10}))
输出
C:\Users\Administrator\AppData\Local\Programs\Python\Python37\python.exe D:/Python/Day02/test.py my name is DaHua i am 10 years old Process finished with exit code 0
isalnum()
str.isalnum() 检查字符串是否仅为字母、数字，或者为字母数字混合，是则返回 True，否则返回 False
print("test123".isalnum())
输出
C:\Users\Administrator\AppData\Local\Programs\Python\Python37\python.exe D:/Python/Day02/test.py
True
Process finished with exit code 0
isalpha()
str.alpha() 检查字符串是否为字母，是则返回True，否则返回False
print("abc".isalpha())
输出
C:\Users\Administrator\AppData\Local\Programs\Python\Python37\python.exe D:/Python/Day02/test.py
True
Process finished with exit code 0
isdecimal()
str.isdecimal() 检查字符串是否只为十六进制
print("000000".isdecimal())
输出
原文：https://www.cnblogs.com/ITkeyan/p/12813056.html