打开文件

如何读写一个文件呢?

0x01 基本用法

Reading files in Python is a common I/O operation, and the built-in open() function provides a simple way to handle it. You can read text or binary files, process them line-by-line, or load the entire content at once depending on your needs.

Reading a Text File

Step 1 – Open the file Use open() with mode ‘r’ for reading text:

with open('example.txt', 'r', encoding='utf-8') as f:
    content = f.read()
    print(content)

This reads the entire file into memory as a string. The with statement ensures the file is closed automatically.

Step 2 – Read line-by-line For large files, read incrementally to save memory:

with open('example.txt', 'r', encoding='utf-8') as f:
    for line in f:
    print(line.strip())

Alternatively, use readline() for manual control or readlines() to get a list of all lines.

Reading a Binary File

When working with images, videos, or other non-text data, use ‘rb’ mode:

with open('image.jpg', 'rb') as f:
    data = f.read()
    print(data[:20]) # Print first 20 bytes

Binary mode prevents Python from decoding bytes into text.

Handling Encodings and Errors

If the file uses a different encoding (e.g., GBK), specify it:

with open('data_gbk.txt', 'r', encoding='gbk', errors='ignore') as f:
    print(f.read())

The errors='ignore' option skips invalid characters.

Best Practices

• Always use with open(...) to ensure proper resource cleanup.

• For huge files, prefer iterating line-by-line instead of loading all content at once.

• Specify encoding explicitly when dealing with non-UTF-8 files to avoid UnicodeDecodeError.

• Use binary mode for non-text data to prevent corruption.

By combining these techniques, you can efficiently and safely read any type of file in Python while managing memory and handling errors gracefully.

Appendix

使用asyncio