Can someone tell me why i get None at the end please this has me stuck for ages

[Gabriel Genellina]

En Mon, 23 Feb 2009 17:22:16 -0200, Gary Wood <woodygar at sky.com> escribió:

> '''exercise to complete and test this function'''
> import string
> def joinStrings(items):
>     '''Join all the strings in stringList into one string,
>     and return the result. For example:
>     >>> print joinStrings(['very', 'hot', 'day'])
>     'veryhotday'
>     '''
>     word = [items]
>     for item in items:
>          print (item, end='')
> def main():
>     print(joinStrings(['very', 'hot','day']))
>     print(joinStrings(['this', 'is','it']))
>     print(joinStrings(['1', '2', '3', '4', '5']))
>
> main()

See this:

py> def sum(a, b):
...   "Returns the sum of two numbers"
...   print a+b
...
py> print sum(2,3)
5
None

The function above does *not* do what is expected. It should compute a+b  
AND RETURN THE RESULT (instead, it PRINTS the result and returns nothing,  
None in Python parlance). It's up to the caller to decide what to do with  
the resultant value; if he wants to print it, fine; but maybe he wants to  
carry on other operations:

py> print sum(2,3) * 4
5
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for *: 'NoneType' and 'int'

If the function claims to *return* something, it should return that thing:

py> def sum(a, b):
...   "Returns the sum of two numbers"
...   return a+b
...
py> print sum(2,3)
5
py> print sum(2,3) * 4
20

Back to your exercise, you have to join the strings together WITHOUT USING  
PRINT. You have to build a NEW string, joining the pieces one by one, and  
return the new, concatenated string. If I'm not mistaken, there were some  
clues in the exercise statement that you're ignoring and should help a lot.

-- 
Gabriel Genellina