Please provide a better explanation of tuples and dictionaries

Daniel W. Rouse Jr. dwrousejr at nethere.comNOSPAM
Wed Jan 30 07:14:42 CET 2013


"John Gordon" <gordon at panix.com> wrote in message 
news:keaa9v$1ru$1 at reader1.panix.com...
> In <hKCdnWgrOqkwFpXMnZ2dnUVZ_qadnZ2d at o1.com> "Daniel W. Rouse Jr." 
> <dwrousejr at nethere.comNOSPAM> writes:
>
>> I have recently started learning Python (2.7.3) but need a better
>> explanation of how to use tuples and dictionaries.
>
> A tuple is a linear sequence of items, accessed via subscripts that start
> at zero.
>
> Tuples are read-only; items cannot be added, removed, nor replaced.
>
> Items in a tuple need not be the same type.
>
> Example:
>
>    >>> my_tuple = (1, 5, 'hello', 9.9999)
>    >>> print my_tuple[0]
>    1
>    >>> print my_tuple[2]
>    hello
>
To me, this looks like an array. Is tuple just the Python name for an array?

> A dictionary is a mapping type; it allows you to access items via a
> meaningful name (usually a string.)
>
> Dictionaries do not preserve the order in which items are created (but
> there is a class in newer python versions, collections.OrderedDict, which
> does preserve order.)
>
> Example:
>
>    >>> person = {} # start with an empty dictionary
>    >>> person['name'] = 'John'
>    >>> person['age'] = 40
>    >>> person['occupation'] = 'Programmer'
>    >>> print person['age']
>    40
>
> Dictionaries can also be created with some initial values, like so:
>
>    >>> person = { 'name': 'John', 'age': 40, 'occupation' : 'Programmer' }
>
Thank you, I understand it better it is kind of like a hash table. 




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