How Can I Read a File Line by Line and Store Each Line in a Python List?

How to Read a File Line-by-Line and Store in a List in Python

To efficiently process large files line-by-line, it is often necessary to read and store each line as an element in a list. Here are various approaches to achieve this:

Reading and Stripping Line Endings:

The following code uses a list comprehension with the rstrip() method to remove any whitespace characters (newlines and spaces) from the end of each line:

with open(filename) as file:
    lines = [line.rstrip() for line in file]

Reading and Processing Line-by-Line:

For large files, it is more efficient to process each line individually without loading the entire file into memory:

with open(filename) as file:
    for line in file:
        print(line.rstrip())

Using the Walrus Operator (Python 3.8 ):

Since Python 3.8 introduced the walrus operator, you can use it to simplify the above loop:

with open(filename) as file:
    while line := file.readline():
        print(line.rstrip())

Specifying File Access Mode and Encoding:

Depending on your file's encoding and intended use, you may want to specify the access mode and character encoding:

with open(filename, 'r', encoding='UTF-8') as file:
    while line := file.readline():
        print(line.rstrip())

These methods provide tailored solutions for various file handling scenarios, ensuring optimal performance and flexibility in working with text files in Python.

The above is the detailed content of How Can I Read a File Line by Line and Store Each Line in a Python List?. For more information, please follow other related articles on the PHP Chinese website!