TypeError: not all arguments converted during string formatting python

The program is supposed to take in two names, and if they are the same length it should check if they are the same word. If it's the same word it will print "The names are the same". If they are the same length but with different letters it will print "The names are different but the same length". The part I'm having a problem with is in the bottom 4 lines.

#!/usr/bin/env python
# Enter your code for "What's In (The Length Of) A Name?" here.
name1 = input("Enter name 1: ")
name2 = input("Enter name 2: ")
len(name1)
len(name2)
if len(name1) == len(name2):
    if name1 == name2:
        print ("The names are the same")
    else:
        print ("The names are different, but are the same length")
    if len(name1) > len(name2):
        print ("'{0}' is longer than '{1}'"% name1, name2)
    elif len(name1) < len(name2):
        print ("'{0}'is longer than '{1}'"% name2, name1)

When I run this code it displays:

Traceback (most recent call last):
  File "program.py", line 13, in <module>
    print ("'{0}' is longer than '{1}'"% name1, name2)
TypeError: not all arguments converted during string formatting

Any suggestions are highly appreciated.


You're mixing different format functions.

The old-style % formatting uses % codes for formatting:

'It will cost $%d dollars.' % 95

The new-style {} formatting uses {} codes and the .format method

'It will cost ${0} dollars.'.format(95)

Note that with old-style formatting, you have to specify multiple arguments using a tuple:

'%d days and %d nights' % (40, 40)

In your case, since you're using {} format specifiers, use .format:

"'{0}' is longer than '{1}'".format(name1, name2)

The error is in your string formatting.

The correct way to use traditional string formatting using the '%' operator is to use a printf-style format string (Python documentation for this here: http://docs.python.org/2/library/string.html#format-string-syntax):

"'%s' is longer than '%s'" % (name1, name2)

However, the '%' operator will probably be deprecated in the future. The new PEP 3101 way of doing things is like this:

"'{0}' is longer than '{1}'".format(name1, name2)

For me, This error was caused when I was attempting to pass in a tuple into the string format method.

I found the solution from this question/answer

Copying and pasting the correct answer from the link (NOT MY WORK):

>>> thetuple = (1, 2, 3)
>>> print "this is a tuple: %s" % (thetuple,)
this is a tuple: (1, 2, 3)

Making a singleton tuple with the tuple of interest as the only item, i.e. the (thetuple,) part, is the key bit here.