Deleting a line in a file

Question

I am having an issue with a timetracker program, where I am trying to identify a line in a file by iterating over it and then writing the lines UNLESS there is anything with

Answer 1

This is reading to the end of the file

print(today.read())

When you start iterating here, you're already at the end

for line in today.readline():

so the for loop will never be entered. You need to reopen the file or seek back to the beginning.

Another problem is that you are iterating over the first line. You probably meant

for line in today:

Regardless, it's generally not a great idea to write to the same file you are reading (eg. consider the mess the file would be in if the computer gets reset partway through)

Better to write a temporary file and replace.

If the files are very small, you could read the file into a list in memory and then rewrite the file out again.

A better idea, before you go too far is to use a database such as the sqlite module (which is builtin to Python)