6.2 The with open() Statement
Learning the recommended and safe way to manage files with the "with" statement, which ensures the file is automatically closed.
Manually using `open()` and `close()` can lead to problems. If, for example, an exception occurs after `open()` but before `close()`, the file may never be closed, leaving system resources tied up. The `with open(...) as ...:` statement is the modern, "Pythonic," and safe way to manage files because it guarantees that the file will be closed automatically, even if an exception occurs within the `with` block.
How Does It Work?
The `with` statement uses a "context manager." In the case of `open()`, the returned file object has two special methods, `__enter__` and `__exit__`. The `with` statement automatically calls `__enter__` at the beginning and, most importantly, guarantees that `__exit__` will be called at the end, which in turn closes the file. This approach makes the code cleaner, shorter, and more robust.
# Example 1: Safe writing with 'with open()'
try:
with open("safe_file.txt", "w", encoding="utf-8") as f:
f.write("This line was written safely.\n")
f.write("The file will be closed automatically.\n")
print("'safe_file.txt' was written and closed automatically.")
except Exception as e:
print(f"An error occurred: {e}")
print("-" * 30)
# Example 2: Safe reading
try:
with open("safe_file.txt", "r", encoding="utf-8") as f:
content = f.read()
print("Content of 'safe_file.txt':\n", content)
except FileNotFoundError:
print("Error: 'safe_file.txt' not found.")Explore More with AI
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