Re: List -> select method
gatesphere <[email protected]> Wed, 24 Oct 2012 20:11:16 -0400
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They all do the same thing, but...
someNums select(isOdd) will just return the list
someNums select(x,writeln(x);x isOdd) will print out each element of the
list, *and* return the odd numbers
someNums select(i,x,writeln("#{i}: #{x}" interpolate); x isOdd) will
print out:
0: 30
1: 10
2: 377
etc.
and return the list.
Basically, the last argument is the only one that's necessary. But in
the examples above, your "x" will act as a reference to the "current
item". And your "i" will act as an incrementing counter as it works
through the list, which due to lists being 0-indexed, is also an index
into the list.
In other terms...
In the first form (someNums select(isOdd)), i and x are implicit.
In the second form (someNums select(x, x isOdd)), i is implicit, x is
explicit.
In the third form(someNums select(i, x, x isOdd)), x == someNums at(i).
Hope this helps?
-->Jake
On 10/24/2012 4:40 PM, Duke Normandin wrote:
>
> Given:
> someNums := list(30, 10, 377, 20, 477, 577)
>
> What's the diff between these three? They all return the same list,
> but I'm sure that I'm not seeing some fine technicality.
>
> Io> someNums select(x, x isOdd)
> ==> list(377, 477, 577)
>
> Io> someNums select(i,x, x isOdd)
> ==> list(377, 477, 577)
>
> Io> someNums select(isOdd)
> ==> list(377, 477, 577)
>
> --
> Duke
> “Tolerance becomes a crime when applied to evil.”― Thomas Mann
>
>
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<p>
<div class="moz-cite-prefix">They all do the same thing, but...<br>
<br>
someNums select(isOdd) will just return the list<br>
<br>
someNums select(x,writeln(x);x isOdd) will print out each element
of the list, *and* return the odd numbers<br>
<br>
someNums select(i,x,writeln("#{i}: #{x}" interpolate); x isOdd)
will print out:<br>
<br>
0: 30<br>
1: 10<br>
2: 377<br>
etc.<br>
<br>
and return the list.<br>
<br>
Basically, the last argument is the only one that's necessary.
But in the examples above, your "x" will act as a reference to the
"current item". And your "i" will act as an incrementing counter
as it works through the list, which due to lists being 0-indexed,
is also an index into the list.<br>
<br>
In other terms...<br>
In the first form (someNums select(isOdd)), i and x are implicit.<br>
In the second form (someNums select(x, x isOdd)), i is implicit, x
is explicit.<br>
In the third form(someNums select(i, x, x isOdd)), x == someNums
at(i).<br>
<br>
Hope this helps?<br>
-->Jake<br>
<br>
On 10/24/2012 4:40 PM, Duke Normandin wrote:<br>
</div>
<blockquote cite="mid:[email protected]" type="cite">
<span> </span>
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<p>Given:<br>
someNums := list(30, 10, 377, 20, 477, 577)<br>
<br>
What's the diff between these three? They all return the
same list, <br>
but I'm sure that I'm not seeing some fine technicality.<br>
<br>
Io> someNums select(x, x isOdd)<br>
==> list(377, 477, 577)<br>
<br>
Io> someNums select(i,x, x isOdd)<br>
==> list(377, 477, 577)<br>
<br>
Io> someNums select(isOdd)<br>
==> list(377, 477, 577)<br>
<br>
-- <br>
Duke<br>
“Tolerance becomes a crime when applied to evil.”― Thomas
Mann<br>
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