[Tutor] Why does the last loop not work?

[Alan Gauld]

On 25/02/14 00:59, Gregg Martinson wrote:

> there is nothing produced.  I am pretty sure it has to do with my syntax
> for the list and the substitution of a a local variable

Chris has answered your question but there are a couple
of general points on your code below...

> def header (r):
>      print ("##############################")
>      print ("### Round: ",r,"            ####")
>      print ("##############################")
>      print ("Aff\tNeg\tJudge\tRoom")

Rather than having multiple calls to print you could do the same thing 
with a single call using a triple quoted string. Its largely a matter of 
taste.

> class Team(object):
>      code = ""

This makes code a class level attribute. I don't think that's
what you want. And you don't seem to use it anywhere.

>      # The class "constructor" - It's actually an initializer
>      def __init__(self,code):
>          self.code = code

This creates an instance attribute which is distinct to your class 
variable above.

>          print ("code is: ",code)
>          self.competitors=[]
>      def print_team(self):
>          print("team code is: ",self.code)
>          print("debated:",end=" ")
>          for x in self.competitors:
>              print (x)
>
>      def debated(self,otherTeam):
>          print (x)
>          self.competitors.append(x)
>      def giveCode(self):
>          return self.code

In Python its idiomatic to not use getter methods like this.
Unless you need to use a method you can just access code
directly.


> def make_team(code):
>      team = Team(code)
>      return team

Unless you u=inrtend to do more magic here this is pretty much redundant.
Calling

spam = make_team(code)

is no better than calling

spam = Team(code)

And it takes more typing, more reading to understand and is slower.

> #MAIN Program#
> myTeamCodes=["a","aa","b","bb","c","cc","d"]
> # Make teams
> myTeams=[]#list of teams
> for x in myTeamCodes:
>      myteam=make_team(x)
>      myTeams.append(myteam)

I don't know if you've discovered list comprehensions yet but this 
pattern is exactly what they do

somelist = []
for item in anotherList:
    somelist.append(somefunc(item)

So when you see that pattern consider replacing it with:

someList = [someFunc(item) for item in anotherList]

Or in your case:

myTeams = [Team(code) for code in myTeamCodes]

HTH
-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.flickr.com/photos/alangauldphotos