(Self-developed artificial intelligence) python string, artificial intelligence python

(Self-developed artificial intelligence) python string, artificial intelligence python

A string is the most commonly used data type in python. We can use single quotation marks ('') or double quotation marks (" ") to create a string.

a='Hello'b="Hello"

All standard sequence operations such as (index, sharding, membership, length, minimum value and maximum value) are also applicable to strings.

Common string formatting symbols:

(% S formatted string)

Print ('hello, % s' % 'World') # Use % s as the placeholder for 'World' Hello, world # result print ('and % s Day' % 10) # using % d as the placeholder for 10 is still 10 days # result # % s can not only format the string, but also format the integer

(% D format integer)

Print ('and % d Day' % 10) # Use % d as a placeholder for 10 and there are 10 days # result

Common Methods for string:

Find (): used to check whether a string contains a substring 'str'. You can specify the start and end ranges.

A = 'hello, world' print (. find ('wo') 6 # returns the index print (. find ('kb')-1 # If no value is found,-1 is returned.

Print (a. find ('wo', 3) # provide the starting point 6 # result print (a. find ('wd ', 6)-1 # result

Print (a. find ('Wo ',) # provide the start and end 6 # result print (a. find ('wd',)-1 # result

Lower (): converts all uppercase characters in a string to lowercase letters.

A = 'hello' B = a. lower () print (B) HeLlo # result

Upper (): converts all lowercase characters in a string to uppercase letters.

A = 'hello' B = a. upper () print (B) HeLlo # result

Swapcase (): converts all lowercase characters in a string to uppercase and lowercase letters to lowercase letters.

A = 'hello' B = a. swapcase () print (B) HeLlo # result

Replace (): replace the old string in the string with the new string.

A = 'Hello world' B = a. replace ('hello', 'Hello') print (B) hello world # result

Strip (): removes the specified character from the beginning and end of a string.

A = '++ hello world ++' B =. strip ('+') print (B) hello world # Result B =. strip ('++ H') print (B) ello world # Result B =. strip ('+ + D') print (B) hello worl # result