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What are the common string operations in Python?
The string is Python.

In common data types, we can use quotation marks ('or ") to create a string, and use and manipulate the string, which requires specific functions. The following are common Python string manipulation methods:

1. Capital ()

Function: capitalize () is mainly used to realize the function of capitalizing the first letter of a string and lowercase other letters.

Example:

1

2str 1 = "oldboy "

print(str 1 . capital())

Output result: old boys

2. Exchange situation ()

Function: swapcase () is mainly used to realize string case inversion.

Example:

1

2str 1 = " Oldboy "

print(str 1.swapcase())

Output result: old boys

3. Title ()

Function: title () is mainly used to realize the non-letter-separated part of a string, with the first letter capitalized and the rest lowercase.

Example:

1

2str 1 = "old boys edu com"

print(str 1.title())

Output result: old boys Edu Com

4. Upper part ()

Function: upper () is mainly used to capitalize all the letters of a string.

Example:

1

2str 1 = "Oldboyedu "

print(str 1.upper())

Output result: OLDBOYEDU

5. Lower part ()

Function: lower () is mainly used to realize that all letters of a string are lowercase.

Example:

1

2str 1 = "oLDBOYEDU "

Print (str 1.lower ())

Output result: oldboyedu

6. Center ()

Function: center () is mainly used to center the string content, and the filler is empty by default.

Example:

1

2

3str 1 = "Oldboyedu "

Print (str 1.center( 15))

print(str 1 . center( 15," * "))

Output result:

Aldboyedu

***Oldboyedu***

7. Find ()

Function: The main function of find () is to find the index by elements, which can be found in whole or in pieces. If it cannot be found, it will return-1.

Example:

1

2

3str 1 = "Oldboyedu "

print(str 1.find('b '))

print(str 1.find('A '))

Output result: 3-1

8. Index ()

Function: The main function of index () is to find the index by elements, which can be searched as a whole or sliced. If it is not found, an error will be reported.

Example:

1

2

3str 1 = " Oldboyedu "

print(str 1.index("b "))

print(str 1.index("A "))

Output result:

Backtracking (last call):

File "",line 1, located at

Wrong value: substring not found.

9. Start with (obj)

Function: The main function of startswith(obj) is to check whether the string starts with obj, and if so, return True, otherwise, return False.

Example:

1

2str 1 = "Oldboyedu "

print(str 1.startswith("O "))

Output result: true

10.endswith(obj)

Function: endswith(obj) is mainly used to check whether the string starts with obj, and if so, it returns True, otherwise it returns False.

Example:

1

2str 1 = " Oldboyedu "

Print (str 1.endswith("edu "))

Output result: true

1 1. Strip ()

Function: The main function of strip () is to remove spaces or other characters, line breaks, tab keys, etc.

Example:

1

2

three

4 str1= "* * old boys * * *"

Print(str 1.strip("*")) # Remove the * sign on both sides.

Print(str 1. lstrip(" * ")# Delete the left *.

Print (str1.rstrip ("*")) # Remove the * sign on the right.

Output result:

old boy

Old boys * * *

** * old boys

12. substitution (oldstr, newstr)

Function: replace(oldstr, newstr) is mainly used to replace strings.

Example:

1

2str 1 = "Oldboyedu "

print(str 1.replace("boy "," man "))

Output result: Oldmanedu

13. Issafa ()

Function: The main function of isalpha () is to judge whether a string consists of only letters, whether it returns true or not, and whether it returns False.

Example:

1

2

three

4str 1 = "Oldboyedu "

Str2 = "old boys edu"

print(str 1.isalpha())

print(str2.isalpha())

Output results: true and false

14.isdigit()

Function: isdigit () is mainly used to judge whether the string is only composed of numbers and whether it returns true.

Example:

1

2

three

4str 1 = "Oldboyedu "

str2 = "520 "

print(str 1.isdigit())

print(str2.isdigit())

Output result: false and true

15. Format ()

Function: The main function of format () is to format strings.

Method 1: Pass parameters by position.

1

2str 1 =' My name is {} and I am {} years old'. Format ("old boys", 30)

Print (str 1)

Output: My name is oldboy, and I am 30 years old.

Method 2: Pass parameters by index.

1

2str 1 =' My name is {0} and I am {1} years old'. Format ('old boys', 30).

Print (str 1)

Output: My name is oldboy, and I am 30 years old.

Method 3: Press the key to pass the parameters.

1

2str 1 =' My name is {name} and I am {age} years old'. Format (age =30, name ='oldboy').

Print (str 1)

Output: My name is oldboy, and I am 30 years old.

16. Count ()

Function: The main function of count () is to count the number of times an element appears in a string.

1

2str 1 = "oldboyedu "

Print (string 1. Count(' o ')# Counts the number of occurrences of the character o in a string.

Data result: 2