[Tutor] Dictionaries of Tuples of Strings

Luke Paireepinart rabidpoobear at gmail.com
Fri Feb 23 22:06:17 CET 2007

Adam Pridgen wrote:
> Hello,
> When I have a tuple with a single string in a dictionary entry and
> try to iterate over the tuple and it breaks the string into individual
> characters.  Is this supposed to be happening?
> This problem is a little tricky to explain so I have included the
> output and the corresponding example code.  In the example I have a
> dictionary with tuples of strings as the values.  If I have more than
> one tuple, I am ok and the value is not broken into individual
> characters (look at the "type="in the code below.  If I have only one
> string in the tuple value, then the string is broken into individual
> characters.  

That's because you can't make tuples of single values.
Parenthesis are ways of controlling order of operation.
They don't create tuples unless there's more than one value.
 >>> x = (((((((((('hello'))))))))))
 >>> type(x)
<type 'str'>
 >>> x = [[[[[[[[[['hello']]]]]]]]]]
 >>> type(x)
<type 'list'>

Think of it like this:
a TUple needs TWO elements or more.
use lists.  They can contain single elements.

When you write
 >>> x = ('somestring')
you might think it's creating a single-value tuple, but it's not.
Consider this:
y = 5
z = 23
x = (y * (z + y) / y ** 3)

In this case you wouldn't expect these parenthesis to build tuples, 
would you?

Hope that helps somewhat,

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