File reading and writing operations in Python

The Python language is a very powerful scripting language and one of the most popular languages ​​in the programming world. In Python, file reading and writing operations are very important and involve almost all programs.

File reading and file writing are two important aspects of data processing. In Python, file reading and writing are implemented through the open() function. The open() function can open a file and return a file object through which we can read and write the file.

File reading operation

In Python, there are many ways to read files. A common way is to use the open() function to open the file, and then use the read() function to read the file contents. The read() function can receive a parameter representing the number of characters or bytes read. If no arguments are specified, the entire file is read.

The following is an example of reading a file:

with open('file.txt', 'r') as file:
    content = file.read()
    print(content)

The above code reads the entire contents of the file by opening a file named file.txt and then using the read() method. After reading the file, the file descriptor is automatically closed. This is achieved by using the with statement.

The following is an example of reading the content of a file of a specified length:

with open('file.txt', 'r') as file:
    content = file.read(10)
    print(content)

The above code only reads the first 10 characters of the file.

File writing operation

In Python, to write to a file, use the open() function to open the specified file, and use the write() method to write the content. If the file does not exist, the open() function will automatically create a new file.

The following is an example of writing data to a file:

with open('file.txt', 'w') as file:
    data = 'Hello, Python!
'
    file.write(data)

In the above code, w mode is used to open the file and then write data.

When writing data to a file, pay attention to distinguishing the differences between different operating modes.

Different options for the mode parameter:

• Read mode (r): Default mode, only read operations can be performed.
• Write mode (w): If the file does not exist, create it, if the file already exists, overwrite the original file.
• Append mode (a): If the file does not exist, create it. If the file already exists, add content to the end of the file.
• Binary mode (b): Add 'b' to the operation mode to enable binary read and write operations.
• Text mode (t): The default mode, which can be understood as adding 't' to the operation mode, which allows text reading and writing operations.

Python provides extremely simple and convenient methods to read and write files, and readers can use them flexibly according to their actual needs. Of course, more advanced file operations are also possible, such as reading web page source code, image files, and even data collected by sensors. File read and write operations connect files and programs and are an indispensable and important feature.

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