Hi all,
I want to do this manipulation. I have an array say @test=[2,4,6,8].
How can i compare a given number against the values which are present in
this array? ie.
In a for loop i will be Iterating through a sequence of number say 1 to
10, and i want to take each of these number 1 to 10 and check if this
number is present in the given array @test, if it is present then i want
to execute some sequence of steps, How can i do this check in ruby ?
Is there a kind of “in” operator in ruby ?
Thank You
Dinesh
ar = [1, 2, 3, 4, 5, 6]
ar.include? 2 => true
@test=[2,4,6,8]
(1…10).each do |n|
if @test.include?(n)
#execute code
end
2006/4/19, Jake McArthur [email protected]:
silly me, should of course be:
@test=[2,4,6,8]
(1…10).each do |n|
if @test.include?(n)
#execute code
end
end
2006/4/19, Dirk M. [email protected]:
On Apr 19, 2006, at 17:45, Dinesh U. wrote:
number is present in the given array @test, if it is present then i
want
to execute some sequence of steps, How can i do this check in ruby ?
Is there a kind of “in” operator in ruby ?
Yes, Enumerable#include?:
irb(main):001:0> 1.upto(10) { |x| puts x if [2,4,6,8].include?(x) }
2
4
6
8
=> 1
– fxn
To expand:
ar = [1, 2, 3, 4, 5, 6]
1.upto 10 do | i |
do_something if ar.include? i
end
If Array was extended with some set theory, things like this would be
possible:
@test.intersect([1…10]).each { |item| puts item }
for i in [2,4,6,8]
puts i
end
There you go, ruining my moment of self-apparent ingenuity. 
Anyway…
(@test & [*1…10]).each { |item| puts item }
From: “Jake McArthur” [email protected]
If Array was extended with some set theory, things like this would be
possible:
@test.intersect([1…10]).each { |item| puts item }
x = [*1…5]
=> [1, 2, 3, 4, 5]
y = [*3…7]
=> [3, 4, 5, 6, 7]
x & y
=> [3, 4, 5]
x | y
=> [1, 2, 3, 4, 5, 6, 7]
x - y
=> [1, 2]
y - x
=> [6, 7]
Regards,
Bill
Dinesh U. wrote:
Is there a kind of “in” operator in ruby ?
It’s backwards from the way you want it.
array.include?(element)
I invite you to go to rcrchive.org and view RCR 241
and vote for it. 
Cheers,
Hal
On 4/19/06, Dirk M. [email protected] wrote:
@test=[2,4,6,8]
(1…10).each do |n|
if @test.include?(n)
#execute code
end
end
On 4/19/06, Matthew M. [email protected] wrote:
Why all that when:
@test.each do |n|
execute code
end
Ah, but what if @test includes elements not in the original loop? Eg:
@test=[2,4,6,8,13]
(1…10).each do |n|
if @test.include?(n)
#execute code
end
end
=> executed for 2, 4, 6, 8
@test.each do |n|
# execute code
end
=> executed for 2, 4, 6, 8, 13
But, in agreeance with other posters in the thread, I’d actually use
some set arithmetic:
([*1…10] & @test).each do |n|
# execute code
end
Of course, this assumes that the elements of the outer loop are known
in advance, as opposed to being generated in a while loop, a
non-expanded large range, etc.
Jacob F.