Use a with statement to close the file buffer and just concatenate strings: with open('file.txt', 'r') as program: data = program.readlines() with open('file.txt', 'w') as program: for (number, line) in enumerate(data): program.write('%d %s' % (number + 1, line))

Feb 28, 2021 · I need to write the line numbers to an already existing text file in python 3. They have asked for the first 5 columns of the text file to contain a 4 digit line number followed by a space.

Sep 14, 2013 · To show line numbers in the current window, go to Options and click Show Line Numbers. To show them automatically, go to Options > Configure IDLE > General and check the Show line numbers in new windows box.

Oct 24, 2024 · In this tutorial, we will explore different methods to add line numbers in Python, providing you with practical examples and code snippets. Why Add Line Numbers? Adding line numbers to your code or text files can significantly enhance readability, especially when sharing code snippets or debugging.

Oct 24, 2024 · Displaying line numbers in your Python code can enhance readability and make it easier to identify specific sections of code during discussions or debugging sessions. It allows developers to quickly reference lines when seeking help or when reviewing code with peers.

May 11, 2024 · The simplest way to add line numbers is by using the built-in `enumerate` function. This function adds a counter to an iterable and returns it as an enumerate object.

Add a trailing backslash (\) The trick is – similar to what you would do in bash, for example – to add a trailing backslash. For example, if I want to print a 1: charon:~ werner$ python >>> print 1 1 >>> print \ ... 1 1 >>> If you write a \, Python will prompt you with ... (continuation lines) to enter code in the next line, so to say.

Oct 28, 2013 · The easiest way to add line numbers to a Jupyter Notebook is to use the keyboard shortcut, which is Ctrl-m to enter Command Mode, then type L. Just highlight the cell you are interested in adding line numbers to, then hit the keyboard shortcut to toggle the line numbers.

Aug 26, 2024 · By following the steps outlined in this article, you can enable line numbers and customize their appearance in IDLE, making it easier to navigate, debug, and collaborate on your Python code.

Oct 13, 2015 · You can use enumerate to keep count of your line number: with open("ourownfile") as f: for line_no, line in enumerate(f, 1): print "{} {}".format(line_no, line)*2, Or using the newer print function (required for python 3): from __future__ import print_function with open("ourownfile") as f: for line_no, line in enumerate(f, 1):