Any reason why this code should not work - The Ruby Way, p270

ribes · May 8, 2008, 2:09pm

I lifted the following code from The Ruby way and tried to use it.
It does not output anything.
Do anyone knows why?

Thank you

Victor

##############################

This code adds a count method to the Array class

This code was lifted from:

The Ruby Way

Second Edition

By: Hal F.

Page: 270

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

@aa = [

[123456789,123456789,123456789,123456789,123456789,123456789,123456789,123456789,123456789],

[123456789,123456789,123456789,123456789,123456789,123456789,123456789,123456789,123456789]
]

@ga = [
        [0,0,0,0,1,9,0,4,0],
        [0,0,4,8,0,0,6,0,0],
        [7,5,0,0,0,0,0,0,2],
        [0,9,0,1,0,2,0,0,4],
        [0,0,0,0,0,3,0,0,0],
        [5,0,0,4,0,6,0,3,0],
        [8,0,0,0,0,0,0,7,3],
        [0,0,6,0,0,8,4,0,0],
        [0,1,0,2,9,0,0,0,0]
        ]

Test the count method:

     f = @ga[0].count
     puts "f = #{f}"           # The output here was: f =

     f = @aa.count
     puts "f = #{f}"           # The output here was: f =

ribes · May 8, 2008, 2:23pm

On Thu, May 8, 2008 at 2:09 PM, Victor R. [email protected]
wrote:

This code was lifted from:

The Ruby Way

Second Edition

By: Hal F.

Page: 270

##############################
class Array
def count
k=Hash.new(0)

```
        self.each{|x| k[x]+1 }
```

```
        self.each{|x| k[x]+=1 }
```

notice the = sign, you have not stored the result anywhere.

ribes · May 8, 2008, 2:27pm

On May 8, 2008, at 8:09 AM, Victor R. wrote:

This code was lifted from:
  end
end

I think it should read:

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

The problem is that inside the ‘each’ loop you’re not asigning any
value.
regards,

ribes · May 8, 2008, 2:29pm

On Thu, May 8, 2008 at 2:09 PM, Victor R. [email protected]
wrote:

This code was lifted from:

The Ruby Way

Second Edition

By: Hal F.

Page: 270

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

I think this line should be
self.each{|x| k[x] += 1}

(notice the = sign, so the value gets assigned to the key).
Otherwise you are never adding entries to the hash

       k
  end

end

Hope this helps,

Jesus.

ribes · May 8, 2008, 2:34pm

Embarrassing!!! To say the least!
Even when I copy, I don’t copy right!

Thank you Jano!

ribes · May 8, 2008, 2:36pm

Yes, Jesus - Thank you!
It is, as I said earlier, embarrassing!

BTW Jesus, on what country are you located? I’m in Brooklyn New York,
USA.

ribes · May 8, 2008, 2:44pm

Thank you Rolando. It was my silly typo!