python - writing to a specific line in text file

Question

I have a text file with the following contents:

name 1,
name 2,
name 3,
...

In python, how do I search for a line and write to it as well?

For example, I want to write to the line beginning with "name 2"

name 1,
name 2,name 1,
name 3,
...

Any help would be greatly appreciated!

Answer 1

Sample Code:

string_to_check = "name 2"
string_to_add = "name 1,"
with open("test.txt", 'r+') as file_to_write:
    lines = file_to_write.readlines()
    file_to_write.seek(0)
    file_to_write.truncate()
    for line in lines:
        if line.startswith(string_to_check):
           line = line.rstrip("\n") + string_to_add + "\n"
        file_to_write.write(line)

Reference no 1 Reference no 2