What are the common operations methods for python files?

General operating steps for files

• Open a file or create a new file: Use the corresponding programming language and the corresponding library or module to open an existing file or create a new file.

• Read file content or write content to the file: To operate the file by reading the file content or writing content to the file, you can use the corresponding methods and functions to fulfill.

• Processing file data: After reading the file content, the file data needs to be processed according to specific needs, such as parsing text data, extracting image information, etc.

• Close the file: After finishing the operation on the file, you must close the file to release system resources and ensure data security.

It should be noted that when performing file operations, you must consider the handling of abnormal situations, such as the file does not exist, does not have read and write permissions, etc.

File reading and writing example

# 打开文件
file = open("example.txt", "r")  # 参数1为文件路径，参数2为打开方式（"r"表示只读）
# 读取文件内容
content = file.read()  # 将文件中所有内容读入到字符串变量content中
# 输出文件内容
print(content)
# 关闭文件
file.close()  # 当文件不再使用时，必须关闭以释放系统资源
# 打开文件
file = open("output.txt", "w")  # 参数1为文件路径，参数2为打开方式（"w"表示写入模式）
# 向文件中写入数据
file.write("Hello, World!")  # 将字符串"Hello, World!"写入到文件中
# 关闭文件
file.close()  # 当文件不再使用时，必须关闭以释放系统资源

In this example, first we use the open() method to open a file named example.txt file and stores it in the variable file. Next, we use the read() method to read all the contents of the file into the string variable content. We then print the contents of that variable and close the file.

Next, we opened the file named output.txt and stored it in the variable file. We then write a string "Hello, World!" to it using the write() method. Finally, we close the file again.

It should be noted that if the file does not exist, an error will occur. When performing file operations, you must always consider the handling of abnormal situations, such as file non-existence, lack of read and write permissions, etc.

File opening method

When opening a file, you need to clearly specify the corresponding opening method to determine the read and write permissions and operation mode of the file. Common file opening methods include:

• r: read-only mode (default). If the file does not exist, an exception is thrown.

• w: Write-only mode. If the file does not exist, create a new file; if the file already exists, clear the file contents.

• #a: append mode. If the file does not exist, create a new file; if the file already exists, append to the end of the file.

• #x: Exclusive mode. Creates a new file, or throws an error if the file already exists.

• #b: Binary mode. When a file is opened using this mode, the file will be operated in binary format, which is suitable for reading and writing non-text files (such as images, videos, etc.).

• #t: Text mode (default). When a file is opened using this mode, the file will be operated in text format and is suitable for reading and writing text files.

• : Read and write mode. Files can be read and written simultaneously.

For example, in Python, to open a file named example.txt in read-only mode, you would use the following code:

file = open("example.txt", "r")

Similarly, to open a file named output.txt in writing mode, you can use the following code:

file = open("output.txt", "w")

It should be noted that after using the opened file, you must use close() method closes the file to release system resources and ensure data security.

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