Question

I read a file which only contains one line. However, I can’t stop reading the file until the loop end. i.e. the python doesn’t throw EOFError exception. what’t wrong with my code?

for x in range(5):
  try:
    line = file.readlines()
  except EOFError:
    break
  print "Line:",line

The output is:

Line: ['nice\n']
Line: []
Line: []
Line: []
Line: []

Answer 1

readlines() reads the whole document and returns the list of lines, not just a single line.

You probably meant to use file.readline() – but even that does not raise an error, so you have to do something else, like checking if not line.endswith("\n"): break or len(line) < 1 to detect the EOF.

Personally I would write the same functionality something like:

with open("filename") as f:
    for i, line in enumerate(f):
        print("Line: %s" % line)
        if i > 5 or not line:
            break

Or if you want to get rid of the extra newlines, change the print statement to:

print("Line: %s" % line.rstrip("\n"))