如果有字符串str = 'zi fu chuan chang jian cao zuo' ,一下是常見的操作
一、find
查找字符串str中是否包含字符串‘fu’和字符串'abc',如果包含就返回索引值，如果不包含就返回-1

In [2]: str = 'zi fu chuan chang jian cao zuo'
In [3]: str.find('fu')
Out[3]: 3
In [4]: str.find('abc')
Out[4]: -1

二、index
查找字符串str中是否包含字符串‘fu’和字符串'abc',如果包含就返回索引值，如果不包含會報錯：1級索引（ABC）沒有找到子串

In [5]: str
Out[5]: 'zi fu chuan chang jian cao zuo'
In [6]: str.index('fu')
Out[6]: 3
In [7]: str.index('abc')
--------------------------------------------------
ValueError       Traceback (most recent call last)
<ipython-input-7-daba474a0c9f> in <module>()
----> 1 str.index('abc')
ValueError: substring not found

三、count
計算字符串str中出現(xiàn)某個字符的次數(shù)（這里為c和b),如果字符串中沒有出現(xiàn)返回 "0"

In [10]: str
Out[10]: 'zi fu chuan chang jian cao zuo'
In [11]: str.count('c')
Out[11]: 3
In [12]: str.count('b')
Out[12]: 0

四、replace
替換字符串str中的字符（比如用‘z’替換‘str’中的'c' -全部；用'a'替換'o',從索引開始數(shù)替換-1次），可以指定替換幾處，默認全部替換

In [15]: str
Out[15]: 'zi fu chuan chang jian cao zuo'
In [16]: str.replace('c','z')
Out[16]: 'zi fu zhuan zhang jian zao zuo'
In [20]: str.replace('o','a',1)
Out[20]: 'zi fu zhuan zhang jian caa zuo'

五、split
以 str 為分隔符切片 ,分隔 出多個子字符串，可以設定最大值

In [24]: str
Out[24]: 'zi fu zhuan zhang jian cao zuo'
In [25]: str.split(' ')
Out[25]: ['zi', 'fu', 'zhuan', 'zhang', 'jian', 'cao', 'zuo']
In [26]: str.split(' ',2)
Out[26]: ['zi', 'fu', 'zhuan zhang jian cao zuo']
In [27]: str
Out[27]: 'zi fu zhuan zhang jian cao zuo'

六、startswith
檢查字符串是否是以'z'開頭，如果是，返回''True'',不是就返回''False''

In [29]: str
Out[29]: 'zi fu zhuan zhang jian cao zuo'
In [30]: str.startswith('z')
Out[30]: True
In [31]: str.startswith('i')
Out[31]: False

七、endswith
和startswith相反，檢查字符串是否是以‘o’結尾，是就返回True ,不是就返回False

In [32]: str
Out[32]: 'zi fu zhuan zhang jian cao zuo'
In [33]: str.endswith('o')
Out[33]: True

八、lstrip
刪除字符串''str'' 左邊的空白字符,不改變原文件

In [35]: str = "      zi fu zhuan zhang jian cao zuo      "
In [36]: str
Out[36]: '      zi fu zhuan zhang jian cao zuo      '
In [37]: str.lstrip()
Out[37]: 'zi fu zhuan zhang jian cao zuo      '

九、rstrip
刪除字符串''str'' 末尾的空白字符,不改變原文件

In [39]: str
Out[39]: '      zi fu zhuan zhang jian cao zuo      '
In [40]: str.rstrip()
Out[40]: '      zi fu zhuan zhang jian cao zuo'
In [41]: str
Out[41]: '      zi fu zhuan zhang jian cao zuo      '

十、strip
刪除字符串''str''兩端的空白字符，不改變原文件

In [42]: str
Out[42]: '      zi fu zhuan zhang jian cao zuo      '
In [43]: str.strip()
Out[43]: 'zi fu zhuan zhang jian cao zuo'
In [44]: str
Out[44]: '      zi fu zhuan zhang jian cao zuo      '

十一、isdigit
檢查字符串''str''中是否只包含數(shù)字，如果只包含數(shù)字則返回 True 否則返回 False.

In [47]: str1 = '123456788'
In [48]: str2 = '12345cigig'
In [49]: str1.isdigit()
Out[49]: True
In [50]: str2.isdigit()
Out[50]: False

十二、join
將一個字符串（str1、str3）當作一個字符插入到另一個字符串中的每一個字符后，造出一個新的字符串，不改變原文件

In [54]: str1 = '1111111111'
In [55]: str2 = '2222222222'
In [56]: str1.join(str2)
Out[56]: '2111111111121111111111211111111112111111111121111111111211111111112111111111121111111111211111111112'
In [57]: str3 = 0
In [59]: str3 = '0'
In [60]: str3.join(str1)
Out[60]: '1010101010101010101'