String splicing
Mode one ： Put two string constants next to each other , It will be spliced when printing
str3 = 'Process finished ''with exit code'
print(str3)
Execution results ： This method is only applicable to the splicing of string constants
Process finished with exit code
Mode two ： Use + Splice two strings
str1 = 'Process finished '
str2 = 'with exit code'
print(str1+str2)
str3 = 'Process finished '+'with exit code'
print(str3)
Execution results ： In this way, string constants and variables can be spliced
Process finished with exit code
Process finished with exit code
Mode three ：join() Method ,join() The list will be （ Or tuples ） Multiple strings in are spliced together using the specified delimiter
my_list = ['www','weipc','top']
print('.'.join(my_list))
str14 = 'x'
print(str14.join("python"))
Execution results ：
www.weipc.top
pxyxtxhxoxn
String and number splicing
Splice strings and numbers , You need to first convert the number from numeric type to string type , have access to str() Method
name = " Li Xiaoyao "
age = 18
info = name + " already " + str(age) + " Year old "
print(info)
Execution results ：
Li Xiaoyao has 18 Year old
Get string length len()
str4 = 'Process finished The process is complete '
# Get string length
print(len(str4))
# Get string adoption UTF-8 Number of bytes when encoding
print((len(str4.encode())))
# Get string adoption GBK Number of bytes when encoding
print((len(str4.encode('gbk'))))
Execution results ：
21
29
25
Find content find()
Used to retrieve whether the specified content exists in the string , If it exists, it returns the index value of the first occurrence of the content in the string , Otherwise, return -1
str5 = 'Process'
print(str5.find('ess'))
print(str5.find('a'))
Execution results ：
4
-1
startswith() and endswith()
startswith() Method is used to determine whether the string starts with the specified string , Is to return True; Instead, return to False.
endswith() Method is used to determine whether the string ends with the specified string , Is to return True; Instead, return to False.
str6 = 'Process'
print(str6.startswith('P'))
# Judge from the specified position of the string
print(str6.startswith('c',3))
print(str6.endswith('s'))
print(str6.endswith('t'))
Execution results ：
True
True
True
False
Count the number of occurrences count()
count Method is used to return the number of times a specified string appears in another string , There is no return 0, Existence returns the number of occurrences .
str7 = 'Process finished in the'
str8 = 'in'
str9 = 'abc'
print(str7.count(str8))
print(str7.count(str9))
# Specify the starting location of the search
print(str7.count(str8,10))
# Specify the starting and ending positions of retrieval
print(str7.count(str8,12,20))
Execution results ：
2
0
1
1
Replace string replace()
replace() Method replaces the old string with the new string .
str10 = 'Process finished'
print(str10.replace('s','x'))
# Specify the maximum number of replacements
print(str10.replace('s','x',2))
Execution results ：
Procexx finixhed
Procexx finished
Split string split()
split() Method to cut a string into multiple substrings according to the specified delimiter , These substrings will be saved to the list （ Does not contain separators ）, Feedback back as the return value of the method .
str11 = 'Process finished with exit code'
print(str11.split(' '))
print(str11.split('i'))
print(str11.split('i',2))
Execution results ：
['Process', 'finished', 'with', 'exit', 'code']
['Process f', 'n', 'shed w', 'th ex', 't code']
['Process f', 'n', 'shed with exit code']
toggle case title()、lower() and upper()
title()： Only convert the initial letter to uppercase , Convert others to lowercase
lower()： Convert strings to uppercase
upper()： Convert string to lowercase
str12 = 'Process finished With EXIT code'
print(str12.title())
print(str12.upper())
print(str12.lower())
Execution results ：
Process Finished With Exit Code
PROCESS FINISHED WITH EXIT CODE
process finished with exit code
Remove spaces and special characters from strings strip(),lstrip(),rstrip()
strip(), Remove spaces or special characters on the left and right sides of the string
lstrip(), Remove spaces or special characters to the left of the string
rstrip(), Remove spaces or special characters on the right side of the string
Special characters refer to tabs （\t）、 A carriage return （\r）、 A newline （\n） etc. .
str13 = ' Process finished with exit code '
print(str13.strip())
print(str13.lstrip())
print(str13.rstrip())
# Remove the character sequence specified at the beginning and end of the string
print(str13.strip('e '))
Execution results ： Returns a copy of the string after the space is deleted , It does not change the original string
Process finished with exit code
Process finished with exit code
Process finished with exit code
Process finished with exit cod
