How to manipulate Python strings

1, go to the space and special symbols

Copy the code code as Follows:

S.strip (). lstrip (). rstrip (', ')

2. Copying strings

Copy the code code as Follows:

#strcpy (sstr1,sstr2)

SSTR1 = ' strcpy '

SSTR2 = SStr1

SSTR1 = ' Strcpy2 '

Print SSTR2

3. Connection string

Copy the code code as Follows:

#strcat (sstr1,sstr2)

SSTR1 = ' strcat '

SSTR2 = ' Append '

SSTR1 + = SStr2

Print SSTR1

4. Find Characters

Copy the code code as Follows:

#strchr (sstr1,sstr2)

# < 0 for not found

SSTR1 = ' STRCHR '

SSTR2 = ' s '

NPos = Sstr1.index (sStr2)

Print NPos

5. Comparing strings

Copy the code code as Follows:

#strcmp (sstr1,sstr2)

SSTR1 = ' STRCHR '

SSTR2 = ' Strch '

Print CMP (sstr1,sstr2)

6. Whether the scanned string contains the specified characters

Copy the code code as Follows:

#strspn (sstr1,sstr2)

SSTR1 = ' 12345678 '

SSTR2 = ' 456 '

#sStr1 and chars both in SSTR1 and SSTR2

Print Len (sStr1 and SStr2)

7. String length

Copy the code code as Follows:

#strlen (sStr1)

SSTR1 = ' strlen '

Print Len (sStr1)

8. Converting uppercase and lowercase characters in strings

Copy the code code as Follows:

S.lower () #小写

S.upper () #大写

S.swapcase () #大小写互换

S.capitalize () #首字母大写

String.capwords (S) #这是模块中的方法. It separates S with the split () function, then uses capitalize () to capitalize the initial letter and merge it with join ().

#实例:

#strlwr (sStr1)

SSTR1 = ' jcstrlwr '

SSTR1 = Sstr1.upper ()

#sStr1 = Sstr1.lower ()

Print SSTR1

9. Append a string of the specified length

Copy the code code as Follows:

#strncat (sstr1,sstr2,n)

SSTR1 = ' 12345 '

SSTR2 = ' abcdef '

n = 3

SSTR1 + = sstr2[0:n]

Print SSTR1

10. String Specified length comparison

Copy the code code as Follows:

#strncmp (sstr1,sstr2,n)

SSTR1 = ' 12345 '

SSTR2 = ' 123BC '

n = 3

Print CMP (sstr1[0:n],sstr2[0:n])

11. Copy Characters of the specified length

Copy the code code as Follows:

#strncpy (sstr1,sstr2,n)

SSTR1 = ' '

SSTR2 = ' 12345 '

n = 3

SSTR1 = sstr2[0:n]

Print SSTR1

12. Replace the first n characters of a string with the specified characters

Copy the code code as Follows:

#strnset (sstr1,ch,n)

SSTR1 = ' 12345 '

ch = ' R '

n = 3

SSTR1 = n * ch + sstr1[3:]

Print SSTR1

13. Scan String

Copy the code code as Follows:

#strpbrk (sstr1,sstr2)

SSTR1 = ' Cekjgdklab '

SSTR2 = ' Gka '

NPos =-1

For C in SStr1:

If C in sStr2:

NPos = Sstr1.index (c)

Break

Print NPos

14. Flip String

Copy the code code as Follows:

#strrev (sStr1)

SSTR1 = ' ABCDEFG '

SSTR1 = sstr1[::-1]

Print SSTR1

15. Find String

Copy the code code as Follows:

#strstr (sstr1,sstr2)

SSTR1 = ' ABCDEFG '

SSTR2 = ' CDE '

Print Sstr1.find (sStr2)

16. Split string

Copy the code code as Follows:

#strtok (sstr1,sstr2)

SSTR1 = ' Ab,cde,fgh,ijk '

SSTR2 = ', '

SSTR1 = Sstr1[sstr1.find (sStr2) + 1:]

Print SSTR1

#或者

s = ' Ab,cde,fgh,ijk '

Print (s.split (', '))

17. Connection string

Copy the code code as Follows:

delimiter = ', '

MyList = [' Brazil ', ' Russia ', ' India ', ' China ']

Print Delimiter.join (mylist)

18, the implementation of Addslashes in PHP

Copy the code code as Follows:

def addslashes (s):

D = {' ': ' \ \ ', ' ' ': ' \ \ ', '/': ' \\\0 ', ' \ \ ': ' \\\\ '}

Return '. join (d.get (c, C) for C in S)

s = "John ' Johny ' Doe (A.K.A. \" Super joe\ ") \\\0"

Print S

Print Addslashes (s)

19. Display only letters and numbers

Copy the code code as Follows:

def onlycharnum (s,oth= "):

S2 = S.lower ();

Fomart = ' abcdefghijklmnopqrstuvwxyz0123456789 '

For C in S2:

If not C in fomart:

s = s.replace (c, ");

Return s;

Print (onlystr ("a000 Aa-b"))

20. Intercepting strings

Copy the code code as Follows:

str = ' 0123456789′

Print str[0:3] #截取第一位到第三位的字符

Print str[:] #截取字符串的全部字符

Print str[6:] #截取第七个字符到结尾

Print str[:-3] #截取从头开始到倒数第三个字符之前

Print str[2] #截取第三个字符

Print str[-1] #截取倒数第一个字符

Print str[::-1] #创造一个与原字符串顺序相反的字符串

Print str[-3:-1] #截取倒数第三位与倒数第一位之前的字符

Print str[-3:] #截取倒数第三位到结尾

Print str[:-5:-3] #逆序截取, What do you mean, you don't understand?

21. String alignment at output

Copy the code code as Follows:

S.ljust (width,[fillchar])

#输出width个字符, s left-aligned, insufficient parts are filled with fillchar, the default is a space.

S.rjust (width,[fillchar]) #右对齐

S.center (width, [fillchar]) #中间对齐

S.zfill (width) #把S变成width长, and right-aligned, less part with 0 complement

22. Search and Replace in string

Copy the code code as Follows:

S.find (substr, [start, [end]])

#返回S中出现substr的第一个字母的标号, Returns-1 If there is no substr in S. Start and End function is equivalent to searching in s[start:end]

S.index (substr, [start, [end]])

#与find () is the same, but when there is no substr in s, a run-time error is returned

S.rfind (substr, [start, [end]])

#返回S中最后出现的substr的第一个字母的标号, If there is no substr in s, then return-1, that is, the first occurrence of substr from the right of the first letter marking

S.rindex (substr, [start, [end]])

S.count (substr, [start, [end]]) #计算substr在S中出现的次数

S.replace (oldstr, newstr, [count])

#把S中的oldstar替换为newstr, count is the number of Replacements. This is a common form of substitution, and there are some functions for replacing special characters

S.strip ([chars])

#把S中前后chars中有的字符全部去掉, It can be understood to replace s before and after chars to none

S.lstrip ([chars])

S.rstrip ([chars])

S.expandtabs ([tabsize])

#把S中的tab字符替换没空格, each tab is replaced by a tabsize space, which defaults to 8

23. segmentation and combination of strings

Copy the code code as Follows:

S.split ([sep, [maxsplit]])

#以sep为分隔符, divide s into a list. Maxsplit represents the number of Splits. The default delimiter is a blank character

S.rsplit ([sep, [maxsplit]])

S.splitlines ([keepends])

#把S按照行分割符分为一个list, Keepends is a bool value that retains the row delimiter after each row is True.

S.join (seq) #把seq代表的序列-string sequence, connected by s

24, the mapping of the string, This function contains two functions

Copy the code code as Follows:

String.maketrans (from, to)

#返回一个256个字符组成的翻译表, where the characters from the from are converted to by one by one, so the from and to must be equal in Length.

S.translate (table[,deletechars])

# Use the above function after the post-natal translation table, the S to translate, and the deletechars of the characters Deleted. It is important to note that if S is a Unicode string, then the Deletechars parameter is not supported, and the same functionality can be achieved by translating a character to None. You can also use the functionality of the codecs module to create more powerful translation Tables.

25, string and a pair of encoding and decoding functions

Copy the code code as Follows:

S.encode ([encoding,[errors]])

# where encoding can have a variety of values, such as gb2312 GBK gb18030 bz2 zlib big5 bzse64, etc. are Supported. The default value for errors is "strict", which means Unicodeerror. Possible values are ' ignore ', ' replace ', ' xmlcharrefreplace ', ' backslashreplace ' and all the values registered by Codecs.register_error. This section covers the codecs module, which is not a specific understanding

S.decode ([encoding,[errors]])

26, the string test, the judgment function, this kind of function is not in the string module, these functions return is the BOOL value

Copy the code code as Follows:

S.startswith (prefix[,start[,end])

#是否以prefix开头

S.endswith (suffix[,start[,end])

#以suffix结尾

S.isalnum ()

#是否全是字母和数字, and has at least one character

S.isalpha () #是否全是字母, and has at least one character

S.isdigit () #是否全是数字, and has at least one character

S.isspace () #是否全是空白字符, and has at least one character

S.islower () #S中的字母是否全是小写

S.isupper () #S中的字母是否便是大写

S.istitle () #S是否是首字母大写的

27, the string type conversion function, These functions only in the string module has

Copy the code code as Follows:

String.atoi (s[,base])

#base默认为10, If 0, then s can be 012 or 0x23 This form of string, if it is 16 then s can only be 0x23 or 0x12 this form of string

String.atol (s[,base]) #转成long

String.atof (s[,base]) #转成float

How to manipulate Python strings