How to use the read() function to read file contents in Python 3.x

How to use the read() function to read file contents in Python 3.x

In Python, the read() function is a very useful function for reading text files. It returns the contents of the file to the program as a string. This article will introduce how to use the read() function to read the contents of a file, with some code examples.

First of all, we need to make it clear that the read() function can only be used to read text files. If we want to read binary files, we need to use readlines() or other suitable functions. Now, let's assume that we already have a text file named example.txt.

The following is a simple example program that shows how to use the read() function to read a text file:

# 打开文件
file = open('example.txt', 'r')

# 使用read()函数读取文件内容
content = file.read()

# 输出文件内容
print(content)

# 关闭文件
file.close()

The first line of the above code opens the file example.txt through the open() function , and name it file. The parameter 'r' means to open the file in read-only mode. If the file does not exist, a FileNotFoundError will be thrown.

Next, we use the read() function to read the file content and assign it to the variable content. This function will read the entire file and return a string. In this way, we can use the variable content to manipulate the content of the file.

Finally, we use the print() function to output the contents of the file. Of course, you can also perform other operations on the file content, such as writing to the database or performing statistical analysis. When we finish reading the file, remember to close the file to release system resources.

In addition to using the read() function to read the entire file, we can also use the read() function to read a specified number of bytes. For example, we can use read(10) to read the first 10 bytes of the file:

# 打开文件
file = open('example.txt', 'r')

# 读取文件的前10个字节
content = file.read(10)

# 输出文件内容
print(content)

# 关闭文件
file.close()

In the above code, the read(10) function will only read the first 10 bytes of the file , and assign it to the variable content. Other operations are similar to the previous code.

In summary, the read() function is a very commonly used function in Python for reading text files. It can easily return the contents of the file to the program as a string. Through the introduction and sample code of this article, I believe you are already familiar with using the read() function to read files. Hope this article is helpful to you!

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