Why this works not right

ruby-talk
1

Hi,

Please take a look at below:

def mytest
   return [1..10]
end

x = mytest
x.each do |c| puts c end

this works not as I expected.
I want the output of:
1
2
3
4
5
6
7
8
9
10

But if I change return [1..10] to return 1..10 it will work.
So what's the difference between 1..10 and [1..10]?
THanks.

2

1..10 is a range, while [1..10] is an array with one element, a range from
1..10. You can think of 1..10 as (1..10) and [1..10] as [(1..10)]

I am 95% sure that this is correct, someone please correct me if I'm wrong.
irb seems to support this:

> def one_to_ten

1..10
end

=> nil

one_to_ten.class

=> Range

[1..10].class

=> Array

3

Eva wrote:

Hi,

Please take a look at below:

def mytest
   return [1..10]
end

x = mytest
x.each do |c| puts c end

this works not as I expected.
I want the output of:
1
2
3
4
5
6
7
8
9
10

But if I change return [1..10] to return 1..10 it will work.
So what's the difference between 1..10 and [1..10]?

1..10 is a Range. [1..10] is an Array with one element (that happens to
be a Range, but that's irrelevant). Range#each returns each element in
the range, so you get 1, 2, 3, etc. Array#each likewise returns each
element in the array -- but your array only has one element, the Range
object itself!

If you want an Array with the elements 1 to 10, you need something like
(1..10).to_a .

THanks.

Best,

···

--
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
--
Posted via http://www.ruby-forum.com/\.

4

Thanks for the reply. I'm newbie to Ruby,so have another question, I
want to make a function who returns the result which can be used as:

mytest do |a,b|c| do_something end

How to write this mytest?

Regards,
Eva

···

On Thu, 2009-12-24 at 11:47 +0900, Steve Klabnik wrote:

1..10 is a range, while [1..10] is an array with one element, a range from
1..10. You can think of 1..10 as (1..10) and [1..10] as [(1..10)]

I am 95% sure that this is correct, someone please correct me if I'm wrong.
irb seems to support this:

> def one_to_ten
> 1..10
> end
=> nil
> one_to_ten.class
=> Range
> [1..10].class
=> Array

5

Eva wrote:

  

1..10 is a range, while [1..10] is an array with one element, a range from
1..10. You can think of 1..10 as (1..10) and [1..10] as [(1..10)]

I am 95% sure that this is correct, someone please correct me if I'm wrong.
irb seems to support this:

> def one_to_ten
    

1..10
end
      

=> nil
    

one_to_ten.class
      

=> Range
    

[1..10].class
      

=> Array
    
Thanks for the reply. I'm newbie to Ruby,so have another question, I
want to make a function who returns the result which can be used as:

mytest do |a,b|c| do_something end

How to write this mytest?

Regards,
Eva

The do...end is actually creating a block, which is passed into your method. There are two ways of having functions accept blocks:

#Explicitly
def mytest &block
  block.call 1, 2, 3
end

#Implicitly
def mytest
  yield 1, 2, 3
end

Either way can be called like

mytest do |a,b,c|
  do_something_with a, b, c
end

You will probably want to read up on methods and blocks and how the two can be used together.

-Justin

···

On Thu, 2009-12-24 at 11:47 +0900, Steve Klabnik wrote:

6

Thanks all!
Merry Christmas Ruby world.

···

--
Kind Regards,
Eva.