Question

I have a large file named CHECKME which is tab delimited. There are 8 columns in each row. Column 4 is integers.

By using Perl or Python, is it possible to verify that each row in CHECKME has 8 columns and that column 4 is an integer?

Answer 1

In Python:

def isfileok(filename):
  f = open(filename)
  for line in f:
    pieces = line.split('\t')
    if len(pieces) != 8:
      return False
    if not pieces[3].isdigit():
      return False
  return True

I assume that by “column no. 4” you mean the 4th one, hence the [3] since Python (like most computer languages) indices from 0.

Here I’m just returning a boolean result, but I split up the code so it’s easy to give good diagnostics about what line is wrong, and how, if you so desire.