[Tutor] Associate functinos with Dictionary/Class Usage

[Danny Yoo]

On Thu, 7 Apr 2005, Luke Jordan wrote:

> I am looking for a little clarification of how exactly this would work.
>
> 1. How do I associate a function to a dict key?


Hi Luke,


We're probably already familiar of values like numbers and strings, and
how to give them names with variables:

######
>>> number = 42
>>> name = "luke"
>>> number
42
>>> name
'luke'
######

'number' is a name that refers to the value 42, and 'name' is a name (Doh!
I must use a better variable name next time...) that refers to the value
"luke".



And we also already know how to make functions and to call them:

######
>>> def square(x):
...     return x * x
...
>>> square(42)
1764
######


But what happens if we just say "square" at the interpreter?

######
>>> square
<function square at 0x40300b1c>
######

The value of 'square' is a function value.


And just like any other value, we can assign it to another name:

######
>>> anotherNameForSquare = square
>>> anotherNameForSquare(16)
256
######


And just like any other value, we can use it as a dictionary value:

######
>>> operators = {'^2': square}
>>> operators['^2']
<function square at 0x40300b1c>
>>> operators['^2'](4)
16
######


Does this make sense so far?  Please feel free to ask more questions about
this.  Best of wishes!