[Newbies] Re: Array questions

[Jerome Peace]

Hi Andreas,

+1.

Shows the difference between thinking about things off the cuff and thinking about things after years of experience,

Though if I were programming things I would do it by using methods on hand rather than invent the new ones for this. We got to get him to read the books. Then the code. 

Cheers --Jer

--- On Fri, 4/23/10, Andreas Raab <andreas.raab at gmx.de> wrote:

> From: Andreas Raab <andreas.raab at gmx.de>
> Subject: [Newbies] Re: Array questions
> To: "A friendly place to get answers to even the most basic questions about Squeak." <beginners at lists.squeakfoundation.org>
> Date: Friday, April 23, 2010, 8:03 PM
> On 4/23/2010 3:48 PM, Jerome Peace
> wrote:
> >> Second, how would i make a method that will return
> the
> >> number of integers in
> >> the array different from the integer parameter
> >> 
> >> anArray howmany: 5   should return
> how many
> >> elements in the array are
> >> different from the number
> > 
> > howMany: anItem
> > 
> > ^(self reject: [ :each |
> >     each = anItem ]) size .
> 
> Better:
> 
> howManyAreNot: anItem
>     "Answer the number of elements different
> from anItem"
> 
>     ^self count:[:each| each ~= anItem]
> 
> Why is that better? 3 reasons:
> 1) The method has a comment.
> 2) The method name tells you what the method does - the
> spec said to answer the number of elements that are NOT the
> argument; the method name should reflect that.
> 3) It uses #count: instead of #reject: making it more
> compact.
> 
> Do note that 1) and 2) really go together. Having a method
> called #howMany: that returns how many items are NOT in the
> collection and no comment clarifying whether the method is
> wrongly named or simply buggy is really problematic.
> 
> Cheers,
>   - Andreas