for - next loop

Even my pickaxe book suggests this should work but it doesn't...

for tax in @taxes
  next if ! (tax.taxauthid === [ 24, 25, 26, 27, 36, 37, 38, 39])
  print tax.taxamount + " - " + tax.taxauthid + "\n"
end

and my thinking is that if the tax.taxauthid is not found in the set of
values, it should jump to the next value of tax.

Why doesn't this work?

Craig

Have you tried replacing the 'next' with another print statement to
see whether it is the logic or the test that is failing? Do I see a
space after the ! ? I have not tried it but Ruby can sometimes be a
bit funny with spaces.

Colin

Hello Craig,

Why don't you use the include? method of Array instead, and get
rid of the negation by using unless. It will make the code easier to
read:

next unless [ 24, 25, 26, 27, 36, 37, 38, 39].include?(tax.taxauthid)

Franz

I am not familiar with 'triple equals' what is the difference between
=== and ==

If I were doing the same thing I'd write it

@taxes.each do |tax|

for tax in @taxes
  next if ! (tax.taxauthid === [ 24, 25, 26, 27, 36, 37, 38, 39])
  print tax.taxamount + " - " + tax.taxauthid + "\n"
end

I may be posting this twice, sorry if thats the case...

Question, what is the difference between === and ==

If I were writing this I would write it with the member? method of
array and avoid the next statement and the negation to make it as
readable as possible.

@taxes.each do |tax|
  if [24, 25, 26, 27, 36, 37, 38, 39].member? tax.taxauthid
    print "#{tax.taxamount}-#{tax.taxauthid}\n"
  end
end

difficult to provide anything more ugly

If I understand correctly, you'd like to output some information about
a selected group of taxes.

How about something like:

selected = @taxes.select { |tax| [24, 25, 26, 27, 36, 37, 38,
39].include? tax.taxauthid }
selected.each { |tax| puts "#{tax.taxamount} - #{tax.taxauthid}" }

Bryan

In most cases that I see (according to the Pickaxe) this is "Case
Equality" that is just a synonym to ==.

Craig White wrote:

Even my pickaxe book suggests this should work but it doesn't...

for tax in @taxes
  next if ! (tax.taxauthid === [ 24, 25, 26, 27, 36, 37, 38, 39])
  print tax.taxamount + " - " + tax.taxauthid + "\n"
end

and my thinking is that if the tax.taxauthid is not found in the set of
values, it should jump to the next value of tax.

Why doesn't this work?

Well, if you're trying to use Array#===, then the array needs to be on
the *left* side of the operator. But I agree that this is an ugly way
of doing things. Probably better is:

@taxes.select{|tax| [24, 25, 26, ...].include? tax.taxauthid}.each do

tax>

  # print stuff
end

Best,

Craig White wrote:
> Even my pickaxe book suggests this should work but it doesn't...
>
> for tax in @taxes
> next if ! (tax.taxauthid === [ 24, 25, 26, 27, 36, 37, 38, 39])
> print tax.taxamount + " - " + tax.taxauthid + "\n"
> end
>
> and my thinking is that if the tax.taxauthid is not found in the set of
> values, it should jump to the next value of tax.
>
> Why doesn't this work?

Well, if you're trying to use Array#===, then the array needs to be on
the *left* side of the operator. But I agree that this is an ugly way
of doing things. Probably better is:

@taxes.select{|tax| [24, 25, 26, ...].include? tax.taxauthid}.each do
>tax>
  # print stuff
end

Craig White wrote:
[...]
> yes, thanks...the .include? worked

Great.

> where the comparison operator === did
> not work for me (or at least I gave up trying)

Why do you say it still didn't work? I explained in my previous message
*exactly* how to get === to work. Please read text, not just code
samples. :slight_smile:

I'd bet I'm not the only one waiting to see your beautiful code. ;p

Pepe