Pythong Handling Files¶
Opening a File¶
To work with files in Python, you use the built-in open() function, which creates a file object. The basic syntax is:
- file_name: The path to the file (absolute or relative).
- mode: The mode in which the file is opened. Common modes include:
'r'for reading (default).'w'for writing, truncating the file first.'a'for appending to a file (writing at the end).'b'for binary mode.'+'for updating (reading and writing).
Creating and Writing to a File¶
Before reading or modifying a file, we first need to create it and write some initial content:
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# Create a file and write initial content
with open('example.txt', 'w') as file:
file.write("Hello, Python!\nWelcome to file IO.")
# Create a file and write initial content
with open('example.txt', 'w') as file:
file.write("Hello, Python!\nWelcome to file IO.")
Reading from a File¶
Now that our file has some content, let’s read from it in different ways:
Reading the Entire Content¶
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with open('example.txt', 'r') as file:
content = file.read()
print(content)
with open('example.txt', 'r') as file:
content = file.read()
print(content)
Hello, Python! Welcome to file IO.
Reading Line by Line¶
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with open('example.txt', 'r') as file:
for line in file:
print(line, end='')
with open('example.txt', 'r') as file:
for line in file:
print(line, end='')
Hello, Python! Welcome to file IO.
Reading Lines into a List¶
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with open('example.txt', 'r') as file:
lines = file.readlines()
print(lines)
with open('example.txt', 'r') as file:
lines = file.readlines()
print(lines)
['Hello, Python!\n', 'Welcome to file IO.']
Appending to the File¶
After reading from the file, you might want to add more content to it:
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with open('example.txt', 'a') as file:
file.write("\nAdding a new line to the file.")
with open('example.txt', 'a') as file:
file.write("\nAdding a new line to the file.")
Reading the Updated File Content¶
After appending new content, let’s read the updated file to see the changes:
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with open('example.txt', 'r') as file:
updated_content = file.read()
print(updated_content)
with open('example.txt', 'r') as file:
updated_content = file.read()
print(updated_content)
Hello, Python! Welcome to file IO. Adding a new line to the file.
Working with Binary Files¶
Although our tutorial has focused on text files so far, handling binary files is also an important aspect of file I/O:
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# Suppose we have an image or any binary data file, we handle it similarly
# Here we use 'example.jpg' as an imaginary binary file that exists in the same directory
with open('example.jpg', 'rb') as file:
content = file.read()
print(content[:20]) # Print the first 20 bytes for illustration.
# Suppose we have an image or any binary data file, we handle it similarly
# Here we use 'example.jpg' as an imaginary binary file that exists in the same directory
with open('example.jpg', 'rb') as file:
content = file.read()
print(content[:20]) # Print the first 20 bytes for illustration.
Handling File I/O Exceptions¶
It’s crucial to manage exceptions that might occur during file operations, such as the file not existing or other I/O errors:
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try:
with open('example.txt', 'r') as file:
content = file.read()
except FileNotFoundError:
print("Sorry, the file does not exist.")
except IOError:
print("Error occurred while handling the file.")
try:
with open('example.txt', 'r') as file:
content = file.read()
except FileNotFoundError:
print("Sorry, the file does not exist.")
except IOError:
print("Error occurred while handling the file.")