What are the string manipulation functions in Python?

As a powerful programming language, Python provides many useful string manipulation functions for processing and manipulating string data. This article will introduce commonly used string manipulation functions in Python and provide some specific code examples.

1. len() function: used to calculate the length of a string.

Sample code:

string = "Hello, World!"
length = len(string)
print("字符串长度为：", length)  # 输出：字符串长度为： 13

2. upper() and lower() methods: Convert strings to uppercase and lowercase letters respectively.

Sample code:

string = "Hello, World!"
print(string.upper())  # 输出：HELLO, WORLD!
print(string.lower())  # 输出：hello, world!

3. strip() method: used to remove whitespace characters at both ends of the string.

Sample code:

string = "   Hello, World!   "
print(string.strip())  # 输出：Hello, World!

4. find() and index() methods: used to find the position of the substring in the original string.

Sample code:

string = "Hello, World!"
print(string.find("World"))  # 输出：7
print(string.index("World"))  # 输出：7

5. count() method: used to count the number of times a certain substring appears in the original string.

Sample code:

string = "Hello, World!"
print(string.count("o"))  # 输出：2

6. replace() method: used to replace the specified substring in the string.

Sample code:

string = "Hello, World!"
new_string = string.replace("Hello", "Hi")
print(new_string)  # 输出：Hi, World!

7. split() method: Split the string into substrings and return a list.

Sample code:

string = "Hello, World!"
strings_list = string.split(", ")
print(strings_list)  # 输出：['Hello', 'World!']

8. join() method: Join strings in a list.

Sample code:

words = ['Hello', 'World!']
string = ", ".join(words)
print(string)  # 输出：Hello, World!

9. isdigit() and isalpha() methods: Used to determine whether a string contains only numbers or letters.

Sample code:

string1 = "123"
string2 = "abc"
print(string1.isdigit())  # 输出：True
print(string2.isalpha())  # 输出：True

Summary: Python provides a wealth of string manipulation functions that can easily complete various string processing tasks. Mastering the usage of these functions is very important for string-related programming tasks. Through the introduction and code examples of this article, I hope readers can better understand and use string manipulation functions in Python.

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