[melbourne-pug] Question about adding members to list : hypothetical just for interest kind of question

[Anthony Briggs]

Sounds like you don't need the checking, since the items are all identical,
*but* if the values differ for a particular key, then the behaviour will be
different (earliest with checking, latest without). It you have itemOne:
10, then itemOne: 20, the checked version will have 10 for itemOne

You can also use the dict() function or dictionary comprehensions to create
your dictionary:
  item = dict( (key, value) for key, value in list )
or
  item = {key: value for (key, value) in list}

Finally, I wouldn't go overriding the builtin list() function with your
variable name though. Call it something less generic, like item_pricing.

Hope that helps,

Anthony



On 21 February 2014 09:31, David Crisp <david.crisp at gmail.com> wrote:

> The following question is more along the lines of "good practice" rather
> than "how do you do it"   .
>
> If I have a name:value list of values that I want to read into a dict for
> ease of lookup, lets define them as:
>
> name  | value
> ==========
> ItemOne : 10
> ItemOne : 10
> ItemOne : 10
> ItemOne : 10
> ItemTwo : 20
> ItemTwo : 20
> ItemTwo : 20
> ItemTwo : 20
> ItemThree : 30
> ItemThree : 30
> ItemThree : 30
> ItemThree : 30
>
> Now,  obviously there are duplicates in that list.    If I use a simple
> loop such as the following:
> for each_name in list:
>      item[name] = value
>
> Then I will get a dict with three pairs in it:
> ItemOne : 10
> ItemTwo : 20
> ItemThree : 30
>
> Which is what I want.
>
> Now,   MY question is,  is there any harm in creating the dict that way
> and looping through all those values multiple times and re-defining the
> values constantly (to the same thing).   OR, should I put a check in there
> such as:
>
> if name not in item:
>    # add name and its pair value to dict
>
>
> In my case I HAVE added checking in but I was wondering if it was really
> needed.  Given no matter what, in either case, the resulting dict would be
> the same.
>
> Regards,
> David
>
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