Python program prints one blank line after reading a text file

Question

I'm doing some simple python exercises in which the target is to simply read a text file and then print it. But my program prints one extra blank line.

Text file is model.txt, which has 3 text rows and 1 blank row, is displayed here

First row
Second row
This is the third row

My program is

file1=open("model.txt","r")
while True:
    row=file1.readline()
    print(row[:-1])
    if row=="":
        break
file1.close()

Now the wanted print result is:

First row
Second row
This is the third row

But instead there is one extra blank line after the print:

First row
Second row
This is the third row

There is a way to remove that one blank line but I haven't been able to figure it out.

`readline()` includes the newline at the end. So the blank line isn't `""`, it is `"\n"`. — John Gordon, Jun 10 '19 at 17:21
https://stackoverflow.com/questions/493386/how-to-print-without-newline-or-space — Luuk, Jun 10 '19 at 17:38

Error - Syntactical Remorse · Accepted Answer · 2019-06-10T17:31:56.067

2

Its because your loop doesn't break soon enough. Read your file like this instead:

with open('model.txt', 'r') as file1:
  for line in file1.readlines():
      trimmed_line = line.rstrip()
      if trimmed_line: # Don't print blank lines
          print(trimmed_line)

The with statement will handle automatically closing the file and the rstrip() removes the \n and spaces at the end of the sentence.

edited Jun 10 '19 at 17:31

answered Jun 10 '19 at 17:21

Error - Syntactical Remorse

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This actually removes the last letter of the last line when I tried it with python3. so doing line.replace("\n","") is probably better ? – painor Jun 10 '19 at 17:29
How does this solve the problem? The input file _actually contains a blank line_ at the end, which he doesn't want to print. – John Gordon Jun 10 '19 at 17:29
@painor I just copied it from his question, I didn't know the reason for it. – Error - Syntactical Remorse Jun 10 '19 at 17:31

score 1 · Answer 2 · answered Jun 10 '19 at 17:20

By default print() adds LF to each line printed, so if your print(row[:-1]) is empty (row[:-1] is empty string) then you still will get that behavior. The workaround would be to replace

print(row[:-1])

with

val = row[:-1]
if val: 
    print(val)

so empty value is not printed.

score 0 · Answer 3 · answered Jun 10 '19 at 17:42

file = open("model.txt", "r") 
for line in file: 
   print(line, end='')

Because the newline is read, it can also print printed with line, no need for line[:-1]

The 'end' option is left here as I need to read this page, filter out some python2 stuff, and then try to understand what that does do ;) How to print without newline or space?

Python program prints one blank line after reading a text file

3 Answers3