How can I add an empty line after a certain linenumber within a text file?-CodePudding

I got a file with 100 lines. I want to delete line 26 till 49 so I did:

import os
l1 = []
with open(r"C:work001.txt", 'r') as fp:
    l1 = fp.readlines()
with open(r"C:work001.txt", 'w') as fp:
    for number, line in enumerate(l1):
        if number not in list (range(25, 49)):
            fp.write(line)

After doing this, the 26th line till 49th line are deleted. But now I want to add an empty line after the 25th line. How can I do that?

CodePudding user response：

A possible solution:

import os
l1 = []
with open(r"C:work001.txt", 'r') as fp:
    l1 = fp.readlines()
with open(r"C:work001.txt", 'w') as fp:
    for line in l1[:25]:
        fp.write(line)
    fp.write("\n")
    for line in l1[49:]:
        fp.write(line)

CodePudding user response：

You can write "\n". \n is an special character that represents a line jump.

CodePudding user response：

This task is simple because you already have the line number:

import os
l1 = []
with open(r"C:work001.txt", 'r') as fp:
    l1 = fp.readlines()

with open(r"C:work001.txt", 'w') as fp:
    for number, line in enumerate(l1):
        if number not in list (range(25, 49)):
            fp.write(line)
        if number == 24:
            fp.write('\n')

This code write an empty line after the 25th line, since the enumerate function count starts from zero, so we check if number == 24, and it's after you write the line variable.