组成字符串的两种方式

a = 'lao'b = 'wang'd = a + be = "===%s===" % (a+b)  #a与b必须都是字符串print(d)print(e)

字符串下标

name = 'abcdef'print(name[0])print(name[5])print(name[len(name)-1])print(name[-1])

字符串切片

name = 'abcdefABCDEF'#切片语法：string[起始位置：终止位置：步长]print(name[2:5])        #cdeprint(name[2:])         #cdefABCDEFprint(name[2:-2])       #cdefABCDprint(name[2:-1:2])     #ceACEprint(name[0:])#以下写法将字符串逆序print(name[-1::-1])         #FEDCBAfedcbaprint(name[::-1])           #前面两个都省略，关键看后面的步长

字符串函数

#coding=utf-8myStr = "hello world and we are the world"print(myStr.count("world"))     #2#统计字符串出现的次数，如果没有则返回0print(myStr.replace("world","WORLD"))       #hello WORLD and we are the WORLD#注意：replace不会对原字符串产生任何影响print(myStr.replace("world","xxxxx",1))     #hello xxxxx and we are the world#replace第一个参数为：要替换的字符串，第二个参数为：替换成什么字符串，第三个参数为：如果要替换的字符串出现多次那么要替换的个数print(myStr.split(" "))         #['hello', 'world', 'and', 'we', 'are', 'the', 'world']print(myStr.capitalize())       #Hello world and we are the worldfile_name = "xxxxx.txt"print(file_name.endswith(".txt"))           #True#ljust , rjust , centerlyric = "Tonight , I feel close to you"print(lyric.center(50))             #          Tonight , I feel close to you           print(lyric.ljust(50))print(lyric.rjust(50))#lstrip , rstrip , stripname = "  who are you "print(name.lstrip())print(name.rstrip())print(name.strip())#partition , rpatitionprint(myStr.partition("world"))         #('hello ', 'world', ' and we are the world')print(myStr.rpartition("world"))        #('hello world and we are the ', 'world', '')#spliteline     按照换行符进行分隔content = "hello\nworld\nxxx\nyyy"print(content.splitlines())                     #['hello', 'world', 'xxx', 'yyy']#isalpha            判断是否是纯字母#isdigit            判断是否是纯数字#isalnum         判断是否是字母与数字#joina = ['aaa','bbb','ccc']b = '='print(b.join(a))                #aaa=bbb=cccb = ' 'print(b.join(a))                #aaa bbb ccc

面试题：给定一个字符串str，返回使用空格或者'\t'分割后的倒数第二个子串

str = "haha nihao a \t heihei \t woshi nide \t hao \npenyou"print(str)sstr = str.split()print(sstr)                 #['haha', 'nihao', 'a', 'heihei', 'woshi', 'nide', 'hao', 'penyou']print(' '.join(sstr))