Python:
Writing a text file
How to:
Using Built-In open() Function
Python’s built-in open() function is the most common way to write to files. The function allows for specifying the mode in which the file is opened - ‘w’ for write (overwriting), ‘a’ for append, and ‘w+’ for write+read.
# Writing to a new file or replacing an existing file
with open('example.txt', 'w') as file:
file.write("Hello, World!\n")
# Appending to a file
with open('example.txt', 'a') as file:
file.write("Appending more text.\n")
# Reading the file to verify
with open('example.txt', 'r') as file:
print(file.read())Sample Output:
Hello, World!
Appending more text.Using pathlib.Path
For a more object-oriented approach, the Path class from the pathlib module offers a method to write to files. This is a popular method for newer Python codebases.
from pathlib import Path
# Writing/Replacing a file
Path('example2.txt').write_text("This is example 2.\n")
# Reading the file to verify
print(Path('example2.txt').read_text())
# Note: `Path.write_text` always overwrites the file content.
# For appending, you'll need to open the file as shown in the previous section.Sample Output:
This is example 2.Third-party Libraries
For complex file operations, third-party libraries like pandas (for CSV, Excel files) can be a great asset. Here’s a quick example of writing a DataFrame to a CSV file using pandas, demonstrating its utility beyond simple text files.
# This example requires pandas: pip install pandas
import pandas as pd
# Creating a simple DataFrame
data = pd.DataFrame({'Column1': [1, 2, 3], 'Column2': ['A', 'B', 'C']})
# Writing DataFrame to a CSV file
data.to_csv('example.csv', index=False)
# Reading the CSV to verify
print(pd.read_csv('example.csv'))Sample Output:
Column1 Column2
0 1 A
1 2 B
2 3 CUsing these methods, Python programmers can effectively manage file operations, catering to both simple and complex data handling needs.