# Building lists

Mon Oct 20 22:55:09 CEST 2014

On Mon, 20 Oct 2014 14:45:19 -0600, Ian Kelly <ian.g.kelly at gmail.com>
wrote:

>On Mon, Oct 20, 2014 at 2:23 PM, Seymore4Head
>> On Mon, 20 Oct 2014 13:58:46 -0600, Ian Kelly <ian.g.kelly at gmail.com>
>> wrote:
>>
>>>On Mon, Oct 20, 2014 at 1:49 PM, Seymore4Head
>>>> For starters I would like to know if you can make a single item list
>>>> and then turn it into a 2 item list.  Is there a command for that?
>>>
>>>You mean like this?
>>>
>>>>>> the_list = ['first_item']
>>>>>> the_list.append('second_item')
>>>>>> the_list
>>>['first_item', 'second_item']
>>
>>
>> a=(1,2,3)
>> b=("Red", "Green", "Blue")
>> c=("a"."b,"c")
>>
>> d=(1,red,a 2,green,b 3,blue,c)
>>
>> Something like that.
>
>Those are tuples, not lists. Are you trying to create a list of tuples
>from a, b, and c? If so, then zip does what you want:
>
>>>> d = list(zip(a, b, c))
>>>> d
>[(1, 'Red', 'a'), (2, 'Green', 'b'), (3, 'Blue', 'c')]
>
>Or do you want all those elements merged into a single list?
>
>>>> d = list(sum(zip(a, b, c), ()))
>>>> d
>
>[1, 'Red', 'a', 2, 'Green', 'b', 3, 'Blue', 'c']

I am not sure really.  I know I need more practice, but I haven't
found a reliable way to find practice problems.

Thank you