Python string methods and operations

Python string methods and 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'))

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)

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.center30,'*'))

Running result

Sdfg
* ************ Sdfg *************

8. encode () Encoding

Change 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:

Sdfdf 1ws
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:

4Traceback (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:

asdfgdAsdFGd

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 () Replacement

Name. replace ('old characters', 'new characters') name. replace ('old characters', 'new characters', 'converted to 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:

['Qwetata', '', '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(),rjust(),__eq__(),partition(),replace(),rsplit(),splitlines(),lstrip(),rstrip(),strip(),join(),index(),format()

2. Be sure to develop the habit: whether it is a tuples, list, or dictionary, add a comma (eg) after the element:str=['1','a',]

Summary

The above is a summary of the methods and operations of python strings introduced by xiaobian. I hope it will be helpful to you. If you have any questions, please leave a message and I will reply to you in a timely manner. Thank you very much for your support for the help House website!