Python _ string operations, python _ string operations

Python _ string operations, python _ string operations
I. String methods and operations

* Note: if the first character is l, it indicates the operation from the left. If the first character is r, it indicates the operation from the right.

1. _ contains _ () determines whether to include

Determines whether a specified character or string is contained in a string. the return value is true or false.

str1="asdfgh"print(str1.__contains__('a'))print(str1.__contains__("df"))print(str1.__contains__('r'))

View Code

 

Running result:

True

True

False

Similar to in

str1="asdf"print('s' in str1)

 

Running result:

True

2. _ eq _ () equal

Determines whether two strings are equal. The return value is True or False.

str1="asdf"print(str1.__eq__("asdf"))print(str1.__eq__("addfd"))

 

Running result:

True

False

3. You can use % s + to add strings.

str1="asd"str2="fgh"str3=str1+str2str4="%s%s"%(str1,str2)print(str3)print(str4)

View Code

 

Running result:

"Asdfgh"

"Asdfgh"

4. format String concatenation

Str1 = "as {0} dsz {1}" result = str1.format ("hu", "ui") print (result) str2 = "as {id} dsfdfz {name}" result = str2.format (id = "hu", name = "ui ") # The variables in the format cannot use print (result) outside)

 

Running result:

"Ashudszui"

"Ashudsfdfzui"

5. Capital of the first letter of the capitalize () String

str1="asdfg"print(str1.capitalize())

 

Running result:

"Asdfg"

6. lowercase letters of casefold ()

str1="ASDFG"print(str1.capitalize())

 

Running result:

"ASDFG"

7. center () center the content with two parameters

# Either a parameter or two parameters, followed by a fill character. The default value is space str1 = "sdfg" print (str1.center (20) print (str1.center (30, '*'))

 

Running result

        sdfg        
*************sdfg*************

8. encode () Encoding

Change the string encoding str1 = "Lan yanru" print (str1.encode ("gbk "))

 

Running result:

B '\ xc0 \ xbc \ xd1 \ xde \ xc8 \ xe3'

9. endswith () determines whether a string ends with a certain character.

str1="asdfdgdghfh"print(str1.endswith('h'))print(str1.endswith('e'))

 

Running result:

True
False

10. expandtabs () converts the tab to space \ t

* Self-thinking is useless

str1="sdfdf\t1ws"print(str1)print(str1.expandtabs())

 

Running result:

sdfdf1ws
sdfdf   1ws

11. find finds the position of a character in the string. If not,-1 is displayed. You can add the start position and end position.

str1="sdgfhfh"print(str1.find('h'))print(str1.find('a'))

 

Running result:

4
-1

12. index return position

Returns the position of the character in the string. If no character is found, an error is returned.

str1="sdgfhfh"print(str1.index('h'))print(str1.index('a'))

 

Running result:

4
Traceback (most recent call last):  File "/usercode/file.py", line 8, in     print(str1.index('a'))ValueError: substring not found

13. join () is used for splicing. "" represents the separator and can be defined.

str1=['s','o','n','g',]print("".join(str1))print(str1)print("-".join(str1))

 

Running result:

song
['s', 'o', 'n', 'g']
s-o-n-g

14. Put ljust () on the left, same as the center

Like the center, the string is located in a row. ljust is located from the left, and the parameter is the length starting from the left.

str1="qeretry"print(str1.ljust(10,'+'’))print(str1.ljust(20,'-'))print(str1.ljust(30))print(str1.ljust(30,'*'))

 

Running result:

qeretry+++
qeretry-------------
qeretry                       
qeretry***********************

15. lower () lower case

All lower case

str1="AsdFGd"print(str1.lower())print(str1)

 

Running result:

asdfgd
AsdFGd

16. lstrip () removes spaces on the left

str1="  ddfd  "print(str1.lstrip())

 

Running result:

ddfd  

17. maketrans () and translate () Methods

These two methods need to be compared and used together

str1="12345"str2="asdfg"aa="afgjdfhd"makes=aa.maketrans(str2,str1)print(aa.translate(makes))

 

Running result:

145j34h3

18. partition ("separated characters ")

str1="woaipython"print(str1.partition("ai"))

 

Running result:

('wo', 'ai', 'python')

19. replace () replace name. replace ('old characters', 'new characters ')
Name. replace ('old characters', 'new characters', 'converted several ')

str1="asdfghjkladadafgasag"print(str1.replace('a','p'))print(str1.replace('a','q',3))

 

Running result:

psdfghjklpdpdpfgpspg
qsdfghjklqdqdafgasag

20. rfind ()

The same method as find is used. The difference is that right-to-left search.

21. Just ust ()

The usage is the same as that of ljust. The difference is that right-to-left lookup.

22. rsplit () specifies characters to split strings

The specified character is deleted.

str1="qwetatrassongsdchengxcxu"print(str1.rsplit('s'))

 

Running result:

['qwetatra', '', 'ong', 'dchengxcxu']

23. splitlines () are separated by line breaks, equivalent to split ('\ n ')

str1='''"aa""bb""cc"'''print(str1.splitlines())str1='''"aa""bb""cc"'''print(str1.splitlines())

 

Running result:

['"aa""bb""cc"']
['"aa"', '"bb"', '"cc"']

24. What does startswith () start?

Determines whether a string starts with a character or string.

str1="adgdfgsdf"print(str1.startswith('a'))print(str1.startswith("ad"))print(str1.startswith("ddd"))

 

Running result:

True
True
False

25. swapcase () case-sensitive conversion. The value is smaller and smaller.

str1="dsDDfFDSSSSSFFqqq"print(str1.swapcase())

 

Running result:

DSddFfdsssssffQQQ

26. title () converts a string into a title, that is, an uppercase letter.

str1="dkjgdkgj"print(str1.title())

 

Running result:

Dkjgdkgj

Ii. Summary

1. Common Methods

Center (), startswith (), ljust (), interval ust () ,__ eq _ (), partition (), replace (), rsplit (), splitlines (), lstrip (), rstrip (), strip (), join (), index (), format ()

2. Make sure that you get into the habit of adding a comma (eg: str = ['1', 'A',]) to the element, whether it is a tuples, list, or dictionary.