I have a text file:

a aaa aaa a

my desired outcome is:

a N aaa N aaa N a N

I wrote the following”
newf="" with open('testfile.txt','r') as f: for line in f: if len(line) < 87: newf+=line.strip()+" " else: newf+=line.strip()+"Nn" f.close() with open('testfile.txt','w') as f: f.write(newf) f.close()

When I run this my outcome becomes

a aaa aaa a

I cant figure out why it changes the output to one line.

adding an if statement for the space length.