1增
str1 = "shi"
str2 = "bei"
str3 = str1 + str2
2删
3改
str1.upper()
str1.lower()
str1.capitalize()
str1.strip()
email = 'de8ug#foxmail.com'
email.replace('#','@') #email.replace(old,new) 结果：'de8ug@foxmail.com'
email.split('#') #去除分隔符，变成列表 结果：['de8ug', 'foxmail.com']
4查
'de8ug'.count('8') #查看某个字符出现的次数 结果： 1
py = 'python is cool'
py.index('is') #查询在哪个位置
py = 'python2 python3 python4 python
py[3] 结果：'h'
5常用方法
'name: %s, place: %s'%(name,city) 结果：'name: de8ug, place: beijing'
'name:{},place:{}'.format(name,city) 结果：'name:de8ug,place:beijing'
