Ruby - test each array element, get one result

Question

I want a one-liner to return true/false, that tests each element in an array for whether it's an Integer or not. So if any element in the array is not an Integer, it should return false, else true. Here's my try:

>> ([2,1,4].map {|x| (x.is_a? Integer)}).reduce {|x, result| x and result}
=> true
>> ([2,"a",4].map {|x| (x.is_a? Integer)}).reduce {|x, result| x and result}
=> false

Any other ideas to distill it down further?

Nakilon · Accepted Answer · 2014-06-12 02:36:04Z

19

array.all?{ |x| x.is_a? Integer }

edited Jun 12, 2014 at 2:36

answered Oct 5, 2010 at 17:12

Nakilon

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Jörg W Mittag · Accepted Answer · 2010-10-05 17:28:29Z

4

ary.all?(&Integer.method(:===))

answered Oct 5, 2010 at 17:28

Jörg W Mittag

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2 Comments

Chuck Over a year ago

I really wish Ruby had a better syntax for accessing methods. This is more conceptually pure, but in practice actually longer than writing out the explicit block.

Jörg W Mittag Over a year ago

@Chuck: Yeah. There is an idea floating around which pops up every couple of years to make a better distintion between the . (message sending) and :: (scope resolution) operators. Currently, . means message sending and :: means scope resulotion or message sending. If we remove the "or message sending" part from ::, we can extend it to allow stuff like foo::bar to mean foo.method(:bar). Currently, that doesn't work, since foo::bar means the same as foo.bar.

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