Ruby array count

Rails
1

Hi Experts,

arr = [1, 2, 3, 5, 5, 2, 5]
is that possible to find whats the count of an value inside an array
“arr”

for example

1 - 1
2 - 2
3 - 1
5 - 3

is that possible?

plz help me guys, its my requirement for specific reasons.

regards,
Bala

2

Hi,

On 29 Okt., 07:06, Bala [email protected] wrote:

arr = [1, 2, 3, 5, 5, 2, 5]
is that possible to find whats the count of an value inside an array
“arr”

One way could be something like this.

arr = [1, 2, 3, 5, 5, 2, 5]
counts = {}
arr.each do |item|
begin
counts[item] = counts[item] + 1
rescue
counts[item] = 1
end
end
counts.each {|k, v| puts “#{k}: #{v}”}

But there probably is some more concise way.

Lutz

3

Hi Lutz,

I got it, but i tried in way using like this

class Array
def count
k=Hash.new(0)
self.each{|x| k[x]+=1 }
k
end
end

a = %w[N1100, N2200, N2200, N1100, N4400]
items = a.count
puts items.inspect

4

Bala wrote:

Hi Lutz,

I got it, but i tried in way using like this

class Array
def count
k=Hash.new(0)
self.each{|x| k[x]+=1 }
k
end
end

a = %w[N1100, N2200, N2200, N1100, N4400]
items = a.count
puts items.inspect

inject is QUITE a powerful tool as well
http://www.ruby-doc.org/core/classes/Enumerable.html#M003171

arr = [1, 2, 3, 5, 5, 2, 5]
arr.inject(Hash.new(0)){|hsh,arr_elm| hsh[arr_elm]+=1 }

worth checking out, a lot of functionality in a one-liner… worth
knowing exists, at the least. hth -

shai

5

Shai R. wrote:

Shai R. wrote:

Bala wrote:

Hi Lutz,

I got it, but i tried in way using like this

class Array
def count
k=Hash.new(0)
self.each{|x| k[x]+=1 }
k
end
end

…btw, these types of questions (pure ruby vs ruby on rails) are great
to ask on the ruby forum - that’s what it is for, and the real experts
seem to lay around there (i’ve seen a DHH and even matz shmooze around
there occasionally)

…and, for example, a thread i’ve just found on
the ruby-forum right at this moment -

http://www.ruby-forum.com/topic/129613

  • guess what it’s about
    ;p
6

Thanks a lot Experts!!! it works perfectly. :slight_smile:

On Oct 29, 12:55 pm, Shai R. [email protected]

7

Shai R. wrote:

Bala wrote:

Hi Lutz,

I got it, but i tried in way using like this

class Array
def count
k=Hash.new(0)
self.each{|x| k[x]+=1 }
k
end
end

…btw, these types of questions (pure ruby vs ruby on rails) are great
to ask on the ruby forum - that’s what it is for, and the real experts
seem to lay around there (i’ve seen a DHH and even matz shmooze around
there occasionally)