structure in Python

[Ben Caradoc-Davies]

On Mon, 20 Oct 2003 18:13:48 -0500, Alberto Vera <avera at coes.org.pe> wrote:
> Hello:
> I have the next structure:
> [key1,value1,value2]
> 
> ['A',1,5]
> ['B',6,7]
> 
> How Can I make it using Python?

You could use a dict of lists of length 2.

    d = {
        "A": [1, 5],
        "B": [6, 7],  # last trailing comma is optional but good style
    }

> How Can I update the value of 6?

6 will always be 6, numbers are immutable, and you can't change it. But you can
change the first item of the list with key "B" with

    d["B"][0] = 2

now

    d["B"]
    
will return [2, 7]

> How Can I insert a key called "C" and its values?

    d["C"] = [8, 9]

> How Can I delete a key called "B"?

    del d["B"]

> How Can I search a key called "A"(parameter) and get its values?

    d["A"]

You could also use multiple assignment to bind variables to the values with

    (value1, value2) = d["A"]

If a key is not found, a KeyError exception is raised. If you prefer, you can
test for the existence of the key with d.has_key("A") . Read the section on
"Mapping types" in the Python Library Reference

    http://python.org/doc/lib/lib.html

which describes the methods of dict objects.

-- 
Ben Caradoc-Davies <ben at wintersun.org>
http://wintersun.org/
Imprisonment on arrival is the authentic Australian immigration experience.