Python学习笔记八:字符串的操作(二)

#coding:utf-8
#两个小函数
#一、查找字符在字符串中第一次出现的位置.
 def find(string, char):
    index = 0
    while index < len(string):
        if (string[index] == char):
            return index
        index += 1
    return -1

 #二、查找字符在字符串中的总数
 def findSum(string, char):
    index = 0
    count = 0
    while index < len(string):
        if (string[index] == char):
            count += 1
        index += 1
    return count

 #使用以上两个函数
print "字符1在字符串1211211234中第一次出现的位置: ", find("1211211234", "1")
print "字符1在字符串1211211234中出现的次数:", findSum("1211211234", "1")

import string  #引入string库
print string.find('www.cctv.com', 'com')   #result=9
print string.find('Good','d')              #result = 3
print string.find('canada', 'a',2,9)       #result =3，用法如下:
#string.find(s, sub[, start[, end]])函数说明
#Return the lowest index in s where the substring sub is found such that sub is
#wholly contained in s[start:end]. Return -1 on failure. Defaults for start and
#end and interpretation of negative values is the same as for slices.
print string.lowercase                     #常量，abcdefghijklmnopqrstuvwxyz
print string.uppercase                     #常量,ABCDEFGHIJKLMNOPQRSTUVWXYZ
print string.digits                        #常量，0123456789

def isLower(char):                        #判断一个字符是否为小写
    if (string.find(string.lowercase, char) > -1):
        return 'Good'
    return 'bad'
print isLower('S')

def isLowertest(char):                   #另外一种判断字符是否为小写的方法
    return  char in string.lowercase
print isLowertest('a')