test = "alex"
v = test.capitalize() #首字母大写
print (v)
v1 = test.casefold()#所有变有小写
print(v1)
v2 = test.lower()
print(v2)
v3 = test.center(20,"#)
print (v3)
结果：########alex########
test = "alexalexr"
v4 = test.count('e')
print (v4)
结果：2
v4 = test.count('e',5)
结果：1
v5 = test.endswith('ex')
v6 = test.startswith('ex')
test = "i am {name},{age}"
v = test.format(name='alex',age=19)
test = "i am [0],[1]"
v = test.format("alex",19")
test = "uasf890"
v = test.isalnum() #只能字母+数字
test = "12345678 9"
v = test.expandtable(6)
结果：12345678 9
test = "as3df"
v = test.isalpha() #是否是字母
False
v = test.isdecimal() 是否数字
v = test.isdigit() 是否数字
v = test.isnumeric() 是否数字，支持中文
test = "alex"
v = test.swapcase() 大小写转换
test = "dsklfsdklf dklsfdf"
v = test.isprintable() #是否存在不可显示
False ( , )
test = " "
isspace(） 是否全部是空格
test = " Return is it ..."
v1 = test.title() 转换为标题
v2 = test.istitle() 是否为标题
test = "nishifengerwoshisha"
print(test)
t = ' '
v = t.join(test)
print (v)
n i s h ...
v = "_".join(test)
n_i_....
test = "alex"
v = test.ljust(20,"*")
结果：alex*************...
v = test.rjust(20,"*")
*************20
v = test.zfill(20)
00000000000000000alex
test = " alex "
test.lstrip() #去左空白
test.rstrip() #去右
test.strip() #去左右
test.lstrip("al") #ex
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必须掌握join,split,find,strip,upper,lower,replace
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len,for,index,切片