Python Tutorial: Edit Specific Line in Text File

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Python Tutorial: Edit Specific Line in Text File

If you’re a Python programmer, there’s a chance that you may encounter the need to edit specific lines in a text file. Whether it’s inserting or deleting a line, or simply modifying a line of code, knowing how to do this can save you time and frustration.

Luckily, editing specific lines in a text file with Python is not only easy, but also quite versatile. There are many different ways to approach this task, depending on your specific needs and the structure of the file you’re working with.

If you’re curious about how to edit specific lines in a text file using Python, look no further than our Python tutorial on this topic. In this tutorial, we’ll cover the basics of working with text files in Python and explore a few techniques for editing specific lines within them. From simple file scans to opening and saving files, we have everything covered.

By reading this tutorial, you’ll learn valuable programming skills that will help you modify text files with ease. So whether you’re a seasoned Python developer or just starting out, dive into our tutorial and discover how easy it is to edit specific lines in a text file using Python!

Editing Specific Line In Text File In Python
“Editing Specific Line In Text File In Python” ~ bbaz


Python is a versatile programming language that offers a wide range of functions and capabilities ideal for working with text files. One of the most critical functionalities of this language lies in its ability to edit specific lines within text files, which is particularly useful for updating or modifying previously written documents. In this blog post, we will explore how Python can help you to edit specific lines in text files, compare different methods and discuss our opinions on which method is the best.

Editing Specific Lines in Text Files

Editing an entire text file can be tedious and time-consuming, but Python can help automate the process by allowing us to edit specific lines. This functionality is achieved using a combination of read, write, and open commands in Python. We can use the lineno() function to locate the specific line we want to change and then use a for loop to modify the text as required.

Method 1: Using Linecache Module

The linecache module is an excellent way to read and cache text files, thus saving time when programmatically accessing lines. This module provides a function called “getline” that returns the contents of a particular line from a file. This method is more suitable for large files where you want to update specific lines at the start or end of the file, but not in the middle of the document.

Method 2: Using “with” Keyword

Using the “with” keyword is a convenient way to open files and provides automatic closing of the file when the block is finished executing. It streamlines the editing process of text files and involves reading the entire text file into memory, processing the changes, and then writing back to the file. With this method, however, you can face some issues when handling very large files, since you need to read the whole file into memory before writing.

Method 3: Using a Temporary File

Increasingly being popular for editing files in Python, this method involves opening a temporary file and writing the modified contents of the document into it. Then, you delete the original text file and then rename the newly edited temporary file. This technique enables a more efficient way of editing files that are not too large, but may cause issues with large files because copying the data to a temporary file can take longer.

Comparison between Methods

Each method discussed above has its advantages and disadvantages, and deciding which one to use will depend on the type and size of the text file that you are working on. In summary:

Method Advantages Disadvantages
Linecache module Fast and efficient handling of large files. May fail to work when lines are altered using numeric indexing or when the target line is in the middle of the file.
Using “with” keyword Convenient and easy to use for small to medium-sized files Not recommended for larger files due to memory issues caused by loading an entire file into memory. May also cause file corruption during editing
A Temporary File Efficient for small to medium-sized files; Copy of data to a temporary file may increase the execution time in large files;


Based on the above comparisons, we think that using a temporary file is the best method for modifying specific lines of text files in Python. This method provides a more efficient and less-complex way to edit small to medium-sized files, especially if you intend to keep a backup copy of the old data. However, this method can be inefficient for larger files, and we recommend either using the linecache module or a combination of both methods for dealing with these scenarios.


Editing specific lines within a text file can sometimes be tedious, but Python makes it easy, efficient and convenient through its open, read, and write functions. With the three methods discussed above, you can modify any line or section of your text files without opening them manually. While each method has its strengths and weaknesses, choosing a suitable method depends on the size and type of the document you are editing. We hope that the comparisons and opinions given in this blog post will assist you in optimally processing text files using Python.

Thank you for reading our Python Tutorial on editing a specific line in a text file without a title. We hope that this guide was able to provide you with valuable information that you can use in your future projects.

Python is an incredibly powerful language that is widely used in the tech industry, and being able to edit and manipulate text files is an important skill to have. Whether you are a beginner or an experienced developer, it is always a good idea to expand your knowledge and learn new tricks and techniques.

If you found this tutorial helpful, we encourage you to check out our other Python guides and resources on this website. We strive to provide quality content that can help you take your coding skills to the next level.

Thanks again for visiting our blog and we hope to see you again soon!

People also ask about Python Tutorial: Edit Specific Line in Text File:

  1. How do I open a text file in Python?
    • You can use the built-in function `open()` to open a file. For example: `file = open(filename.txt, r)`
  2. How do I read specific lines from a file?
    • You can use the method `readlines()` to read all the lines in the file and then access specific lines using indexing. For example: `lines = file.readlines()` and then `print(lines[0])` for the first line.
  3. How do I edit a specific line in a text file?
    • You need to open the file in write mode, read all the lines, modify the specific line, and then write the modified lines back to the file. For example: “` with open(filename.txt, r) as file: lines = file.readlines() lines[2] = This is the new line.\n with open(filename.txt, w) as file: file.writelines(lines) “`
  4. Can I append a new line to a text file?
    • Yes, you can open the file in append mode and use the method `write()` or `writelines()` to add a new line. For example: “` with open(filename.txt, a) as file: file.write(This is a new line.\n) “`

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