Question

I have a text file (file1.txt) with 1 string per line over many lines.
I’m trying to read in the file and write certain lines to a new file.(file2.txt)

My text file looks something like this.

foo1
foo2
foo3
foo4
foo5
foo6

etc..

for example, i want to write foo1,foo2,foo4,foo6 to my new file and miss out foo3 and foo5.

foo1
foo2
foo4
foo6

I wish to preserve the original file.

My code looks like this…

with open("file1.txt","r") as r:
    lines=r.read()
    lines =lines.replace("foo3","")
    lines = lines.replace("foo5","")

r.close()
with open("file2.txt","a") as w:
    w.write(lines)
w.close

The problem is I end up with this output..

foo1
foo2

foo4

foo6

I think this is because i am replacing foo with “”
how do I get rid of the white space?

TIA,

Paul.

Answer 1

The minimal change is to also replace the line separators by changing the replace calls to:

lines =lines.replace("foo3\n","")
lines = lines.replace("foo5\n","")