python programming help

[rurpy at yahoo.com]

On 12/08/2013 12:17 PM, Chris Angelico wrote:
> On Mon, Dec 9, 2013 at 6:06 AM,  <rafaellasav at gmail.com> wrote:>[...]
> Also, your posts are acquiring the slimy stain of Google Groups, which
> makes them rather distasteful. All your replies are getting
> double-spaced, among other problems. Please consider switching to an
> alternative newsgroup reader, or subscribing to the mailing list:
> https://mail.python.org/mailman/listinfo/python-list

To the OP:

First, my apologies if my reply ends up trashing your 
discussion here, but you should know what is behind Mr.
Angelico's response.

For some time now the Google Group Wars are being fought
in this group.

There is a (probably very small) clique of Google haters 
who try present themselves as "the community" and who try
to intimidate anyone posting from Google Groups into using
some other means of posting, completely disregarding the
fact that for many new people or occasional posters, Google 
Groups is an order of magnitude easier to use.  These people
are extremely noisy and obnoxious but *do not* represent 
"the community" except in their own minds.  I suspect many 
of them are motivated by political dislike of Google as 
a corporation, or want to stay with the 1990's technology 
they invested time in learning and don't want see change.

I and many other people post here from Google Groups and 
you should feel free to too if it is more convenient for 
you.  (Of course you can also use the maillist or usenet 
if you find them a good solution for *you* but please don't 
feel compelled to by some loud obnoxious bullies.)

As another poster pointed out, if you are able to follow 
some of the advice at,

  https://wiki.python.org/moin/GoogleGroupsPython

it will help quiet down the anti-Google crowd a little but
even if you don't, those without a Google chip on their shoulder 
will simply skip your posts if they find the Google formatting
too annoying.  Most of us though will deal with it as adults 
and try our best to answer your questions.

I just thought you should have both sides of the story so
to won't take the anti-Google crowd here as gospel.

Addressing you last question, I presume you understood the
other responses about replacing the "print (people)" 
statement in your people() function with "return people".

The only additional thing I wanted to add is that, 

  people=[name for name in dic if dic[name]==age] 

is (I would guess) a rather advanced way of doing what 
you are doing, given where you seem to be in learning
about python (but maybe not, in which case ignore the 
following).

The [....] thing is called as "list comprehension and 
in described here
  http://docs.python.org/3/tutorial/datastructures.html#list-comprehensions

However, it is just a more concise way of writing:

  people = []
  for n, a in dic.items():
    if a == age: people.append (n)
  return people

To understand the above (if you don't already) you'll want 
to read about the the items() method of dicts:
  http://docs.python.org/3/tutorial/datastructures.html#looping-techniques
  http://docs.python.org/3/library/stdtypes.html#mapping-types-dict
the append() method of lists, 
  http://docs.python.org/3/tutorial/controlflow.html#for-statements
  http://docs.python.org/3/library/stdtypes.html#mutable-sequence-types
and of course "for" loops;
  http://docs.python.org/3/tutorial/controlflow.html#for-statements

Hope this helps.