trying to understand dictionaries
Jean-Michel Pichavant
jeanmichel at sequans.com
Fri Jun 12 08:25:37 EDT 2009
Basically, dictionaries are a bunch of couples of key and value where
key is an immutable object. In fact you'll find a more accurate
definition in any python book or online tutorial.
The thing is that keys are usually used as an easy and quick way the
search and index items.
You can see dict as a list that can use strings instead of integers to
index its values.
phonebook = {
'ricky' : ('ricky', 'martin', 'male'),
'britney' : ('britney', 'spears', 'female'),
'myBestBuddy' : ('barack', 'obama', 'male'),
42 : ('bob', 'bib', 'male'), # you can use 42 as index, like strings
integers are not mutable
True: ('', '', ''), # meaningless example just to show that any
immutable object will fit as index
}
fname, ename, gender = phonebook['myBestBuddy']
fname, ename, gender = phonebook[42]
Keys are unique among the dictionary.
Jean-Michel
khemeia at gmail.com wrote:
> Hi.
> As the subject says, I'm a newbie trying to learn python and now
> dictionaries. I can create a dict, understand it and use it for simple
> tasks. But the thing is that I don't really get the point on how to
> use these in real life programing.
>
> For example I tryed to create a very simple phonebook
>
> code:
>
> d = {'fname': [], 'ename': []}
> name1 = 'ricky'
> name2 = 'martin'
> d['fname'].append(name1)
> d['ename'].append(name2)
>
> name1 = 'britney'
> name2 = 'spears'
> d['fname'].append(name1)
> d['ename'].append(name2)
>
>
> This gives me:
> {'ename': ['martin', 'spears'], 'fname': ['ricky', 'britney']}
>
> I wonder if this is a correct usage and thinking about dictioaries in
> python.
> Everything in my example is based on a serval lists in a dictionary,
> and person 1 is == ename[0] & fname[0]
> and person 2 is == ename[1] & fname[1], it's based on position and
> indexing.
>
> Is this correct if no, how would you do it?
> if yes, how can I print the result out in a nice way? I need a for-
> loop that prints:
> all [0] in all lists
> all [0] in all lists and so on.
>
>
> thanks
> /jonas
>
>
More information about the Python-list
mailing list