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python开发之字符串string操作方法实例详解

Jun 10, 2016 pm 03:07 PM
python python string string string How to operate

本文实例讲述了python开发之字符串string操作方法。分享给大家供大家参考,具体如下:

在python中,对于字符串string的操作,我们有必要了解一下,这样在我们的以后的开发中会给我们带来很多方便

下面是我学习的笔记:

#python-string
#python中的字符串用单引号''和双引号""标示
strA = 'this is a string'
strB = "this is a message!"
#打印两个字符串
print("打印两个字符串")
print('strA = ' + strA)
print('strB = ' + strB)
print("#############################")
strC = 'I don\'t know anything'
strD = '\'Yes\',I know.'
print("字符串中的转义字符")
print('strA = ' + strC)
print('strB = ' + strD)
print("#############################")
strE = '这是我的blog,欢迎大家来\n我的博客溜达'
print("字符串中的换行")
print('strA = ' + strE)
print("#############################")
strF = 'this is ''message'
strG = 'Hongten'
strH = strG * 3
print('字符串可以用\'+\'号连接(或者说粘合),也可以用\'*\'号循环')
print('strF原有形式为:\'this is \'\'message\'')
print('粘合后的strF:' + strF)
print('strG原值为:\'Hongten\',strH = strG * 3,此时strH为:' + strH)   
print("#############################")
strI = 'hongtenzone@foxmail.com'
print('字符串可以使用下标(索引)查询')
print('源字符串strI = \'hongtenzone@foxmail.com\'')
print('字符串strI的长度,len(strI) = ')
print(len(strI))
print('strI[0] = ' + strI[0])
print('strI[10] = ' + strI[10])
print('strI[-1] = strI[len(strI) - 1]')
print('strI[-1] = ' + strI[-1])
print('strI[len(strI) - 1] = ' + strI[len(strI) - 1])
print("#############################")
print('Python 字符串不能改写。按字符串索引赋值会产生错误:')
print('strI[0] = \'x\',这样就会产生错误啦')
print("#############################")
print('过大的索引代替为字符串大小,下界比上界大的返回空字符串')
print('strI[0:100] = ' + strI[0:100])
print("#############################")
print('索引可以是负数,计数从右边开始')
print('strI[-2] = ' + strI[-2])
print('strI[-23:] = ' + strI[-23:])
print("#############################")
print('不过-0 还是0,所以它不是从右边计数的!')
print('strI[0] = ' + strI[0])
print('strI[-0] = ' + strI[-0])

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运行效果如下:

Python 2.7.9 (default, Dec 10 2014, 12:24:55) [MSC v.1500 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> ================================ RESTART ================================
>>> 
打印两个字符串
strA = this is a string
strB = this is a message!
#############################
字符串中的转移字符
strA = I don't know anything
strB = 'Yes',I know.
#############################
字符串中的换行
strA = 这是我的blog,欢迎大家来
我的博客溜达
#############################
字符串可以用'+'号连接(或者说粘合),也可以用'*'号循环
strF原有形式为:'this is ''message'
粘合后的strF:this is message
strG原值为:'Hongten',strH = strG * 3,此时strH为:HongtenHongtenHongten
#############################
字符串可以使用下标(索引)查询
源字符串strI = 'hongtenzone@foxmail.com'
字符串strI的长度,len(strI) = 
23
strI[0] = h
strI[10] = e
strI[-1] = strI[len(strI) - 1]
strI[-1] = m
strI[len(strI) - 1] = m
#############################
Python 字符串不能改写。按字符串索引赋值会产生错误:
strI[0] = 'x',这样就会产生错误啦
#############################
过大的索引代替为字符串大小,下界比上界大的返回空字符串
strI[0:100] = hongtenzone@foxmail.com
#############################
索引可以是负数,计数从右边开始
strI[-2] = o
strI[-23:] = hongtenzone@foxmail.com
#############################
不过-0 还是0,所以它不是从右边计数的!
strI[0] = h
strI[-0] = h
>>>
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print打印字符串语句如下:

print('理解切片的最好方式是把索引视为两个字符之间的点,第一个字符的左边是0,字符串中第n个字符的右边是索引n')
print(' +---+---+---+---+---+ ')
print(' | H | e | l | p | A |')
print(' +---+---+---+---+---+ ')
print(' 0  1  2  3  4  5 ')
print('-5 -4 -3 -2 -1 -0')
print('第一行是字符串中给定的0到5各个索引的位置,第二行是对应的负索引。从i 到j 的切片由这两个标志之间的字符组成')
print('对于非负索引,切片长度就是两索引的差。例如,word[1:3] 的长度是2')

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运行效果如下:

Python 2.7.9 (default, Dec 10 2014, 12:24:55) [MSC v.1500 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> ================================ RESTART ================================
>>> 
理解切片的最好方式是把索引视为两个字符之间的点,第一个字符的左边是0,字符串中第n个字符的右边是索引n
 +---+---+---+---+---+ 
 | H | e | l | p | A |
 +---+---+---+---+---+ 
 0  1  2  3  4  5 
-5 -4 -3 -2 -1 -0
第一行是字符串中给定的0到5各个索引的位置,第二行是对应的负索引。从i 到j 的切片由这两个标志之间的字符组成
对于非负索引,切片长度就是两索引的差。例如,word[1:3] 的长度是2
>>>

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希望本文所述对大家Python程序设计有所帮助。

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