Python Read Text File Line by Line Example
Hi Guys,
In this tutorial, we will explore different methods to read a text file line by line in Python. This is a common operation in many programming tasks such as data processing, file manipulation, and log file analysis. We will cover the best approaches to efficiently read text files line by line and store them in an array.
Python provides multiple ways to read files, including the readlines() method and iterating over the file object using a for loop. These methods ensure efficient memory usage, especially for large files.
Let’s look at the examples below:
Example 1: Using readlines()
The readlines() method reads all lines from a file and returns them as a list of strings.
main.py
# Python read text file using readlines()
with open('readme.txt') as f:
lines = f.readlines()
print(lines)
Output
['Hi stuffcoder.com!\n', 'This is body\n', 'Thank you']
Example 2: Using a For Loop (Efficient for Large Files)
The for loop method is more memory-efficient because it reads one line at a time, making it suitable for large files.
main.py
with open('readme.txt') as f:
for line in f:
print(line.rstrip())
Output
Hi stuffcoder.com! This is body Thank you
Both methods are useful depending on your use case. If you need to process large files efficiently, the for loop method is recommended. If you need all lines at once for further manipulation, use readlines().
Frequently Asked Questions (FAQs)
1. How do I read a file line by line in Python?
You can use the readlines() method or a for loop to iterate over the file object line by line.
2. What is the best way to read large files in Python?
The best way to read large files efficiently is by using a for loop to iterate over the file object.
3. How do I remove newline characters while reading a file?
You can use the rstrip() method to remove newline characters while reading a file.
4. How do I store file lines in a list?
You can use readlines() to read all lines into a list or append lines to a list using a loop.
5. Can I read a file without loading it all into memory?
Yes, using a for loop allows you to read and process one line at a time without loading the entire file into memory.
Hope this tutorial helps! Happy Pythonic Coding!