command def function inside the raw_input?

Question

I have a def function looks like:

def update(marks, num, mark, column):
    lines = [l for l in marks]
    for row in range(len(all_marks)):
        if all_marks[row][0] == num:
            lines[row][column] = mark
        elif lines[row][column] != '':
            print num + ' already has a value in column - update ignored.'

and raw_input function inside another def function looks like:

result1 = raw_input('Enter results file: ')
num = raw_input('Student number (empty to finish): ')

if len(snumber) == 0:
    print
    print
    print 'finished'
    print
    print
    return interact()

 else:
    pass

 column2 = raw_input('Enter column: ')
 newresult1 = raw_input('New result: ')

 try:
     print update(result1, snumber, newresult1, column2)

 except IOError:
    print 'Try again'

The third line from the bottom supposed to print def update(marks, num, mark, column) but it keeps returning none.

Sorry, the codes are a bit messy. Can anyone let me know what I have done wrong?

Thanks in advance.

Answer 1

Your update function doesn't look like it returns anything. You need to explicitly return something or there won't be a return value.

Answer 2

raw_input() prompts the user and returns the user's response as a string . You're probably looking to convert the string into an integer.

This code will nag the user until a proper response is given:

while True:
  try:
    column2 = int(raw_input('Enter column: '))
    break
  except ValueError:
    print 'You did not supply an integer!'