Collect value

rubyonrails-talk
1

Hi Everyone,

Good Day,

a=[ ‘casual’,‘sick’,‘casual’,‘sick’,‘casual’,‘sick’,‘casual’,‘sick’ ]

I need to collect casual’s count and sick’s count like,

Caual :4

Sick :4

Thank you,

2

we can use a.count(“casual”) and viceversa.

3

thanks :slight_smile:

4

I tend to use a method like:

module Enumerable

Returns a Hash keyed by the value of the block to the number times that

value was returned. If you have experience with the #group_by from

ActiveSupport, this would be like .group_by(&block).map{|k,a|[k,a.size]}

(except it is a Hash rather than an Array).

def count_by

counts = Hash.new(0)

each {|e| counts[block_given? ? yield(e) : e] += 1}

counts

end

end

$ irb -r ./enumerable

irb1.9.3> a=[ ‘casual’,‘sick’,‘casual’,‘sick’,‘casual’,‘sick’,‘casual’,‘sick’ ]

#1.9.3 => [“casual”, “sick”, “casual”, “sick”, “casual”, “sick”, “casual”, “sick”]

irb1.9.3> a.count_by

#1.9.3 => {“casual”=>4, “sick”=>4}

This keeps you from iterating over the source multiple times, too.

-Rob

5

Please do not teach people to monkey patch a class directly, if you plan to play dirty and reopen a class be nice enough to make your own module and then send(:include, MyModuleExt) so that people know where it is coming from easily, rather than leaving people in the dark as to what the hell is going on when they start looking for the method in the stdlib docs.