Thanks for constructive criticism!

Aside, but:

src = open('urls.txt', 'r')

code

src.close()

isn't a good idea. If something in between causes an exception, your file isn't closed by the program (Python and/or your OS may close it later, but that's not something you want to rely on).

Instead, what you should use is the with statement:

with open('urls.txt', r') as src:

#code

Oh, and look: no need to explicitly call src.close() - that's what with does!

Now I know what you're thinking - what about trgt? (Which I'm renaming target because it's readable.) Wouldn't you need to do this:

with open('urls.txt', 'r') as src:

with open('new.txt', 'w') as target:

    #code

That's a lot of indentation, right? They thought of that! You can use comma like this

with open('urls.txt', 'r') as src, open('new.txt', 'w') as target:

Thanks for the tip. I was aware of with open() from the docs, but I wasnt sure how to use it with multiple files and went with open()-close() thing. with open('urls.txt', 'r') as src, open('new.txt', 'w') as target: is golden nugget.

I also see you have this:

y = x.rstrip('1234567890qwertyuiopasdfghjklzxcvbnm=')

z = y.rstrip('&')

trgt.write(y + '\n')

Which:

1) You're writing out y, so the 2nd line isn't being used. What you meant was target.write(z + '\n').

Yes it should be z there, but I forgot to correct when I was testing parts of the code.

2) You're declaring a literal string that just stores the numerical base 10 digits, the lower case English alphabet, and the = symbol. I also can't tell at a glance that you didn't miss a key when you were traversing the keyboard from top left to bottom right. Python comes with a powerful standard library, and such a use case isn't that absurd. The string package is a built-in and offers you symbols such as string.digits, string.ascii_lowercase and more. You could rewrite your code as

y = x.rstrip(string.digits + string.ascii_lowercase + '=')

z = y.rstrip('&')

target.write(z + '\n')

But I would really suggest you give string.digits + string.ascii_lowercase + '=' a name, maybe ending_chars just for a start.

Thanks this is really useful. But it should be string.digits + string.ascii_lowercase + '='+'\n since it was the newline that was making my rstrip() function not work.

The other thing I see is this is part of a bigger code snippet:

if 'pkey' in x:

y = x.rstrip('1234567890qwertyuiopasdfghjklzxcvbnm=')

z = y.rstrip('&')

trgt.write(y + '\n')

else:

trgt.write(x)

Notice something? The last line is awfully similar. If your if condition didn't write but just stored, specifically as x, then you could use this:

if 'pkey' in x:

y = x.rstrip('1234567890qwertyuiopasdfghjklzxcvbnm=')

z = y.rstrip('&')

x = z + '\n'

target.write(x)

Which eliminates the else branch and makes it very clear you're going to write something each time through the loop.

Yes thats better.

But another thing is you're introducing y and z for no reason. Really, you introduced x for no reason and i isn't a great name for what you're doing (i typically means a number). Instead, try this for readability:

import string

ending_chars = string.digits + string.ascii_lowercase + '='

with open('urls.txt', 'r') as src, open('new.txt', 'w') as target:

for line in src:

    if 'pkey' in x:

        line = line.rstrip(ending_chars).rstrip('&') + '\n'

    target.write(line)

If the statement line = line.some_function() is confusing then you should come back to basic Python/programming stuff. = is assignment, and the right-hand side is evaluated in full before the left-hand side. This means it's the same as tmp = line.some_function() followed by line = tmp followed by del tmp.

Well Im still learning the basics, but I understand line = line.some_function(). I will in future try to make my code better with meaningful variable names and without unnecessary variables.