Prev: Cheap Wholesale Chanel Boots (free shipping)
Next: Why do I get undefined method?
From: Abder-rahman Ali on 13 Jul 2010 04:40
I'm trying to write a script that lists ONLY the keys in a hash as
follows: http://pastie.org/private/1ruahb5w05ihsloqwmqeng

The case is that when I run the script, I get the following:

NameAbder-Rahman Ali
Age26

While, I'm intending to get

Name
Age

What am I missing in the script?

Thanks.
--
Posted via http://www.ruby-forum.com/.

From: Stefano Crocco on 13 Jul 2010 04:56
On Tuesday 13 July 2010, Abder-rahman Ali wrote:
> |I'm trying to write a script that lists ONLY the keys in a hash as
> |follows: http://pastie.org/private/1ruahb5w05ihsloqwmqeng
> |
> |The case is that when I run the script, I get the following:
> |
> |NameAbder-Rahman Ali
> |Age26
> |
> |While, I'm intending to get
> |
> |Name
> |Age
> |
> |What am I missing in the script?
> |
> |Thanks.

As you can see from the documentation (for example, with ri Hash#each),
Hash#each yields two arguments to the block: the key and the corresponding
value. Since your block only takes one argument, ruby puts both in an array,
whose to_s method produces a string with the two elements one after the other.

If you only want the key, you can use each_key rather than each, since this
will only pass the block the keys:

personal_information.each_key{|k| puts k}

If you want to use each (but you don't need to in your example), you can have
the block take two parameters and only use the first (the key):

personal_information.each{|key, val| puts key}

or have the block take a single argument (which will be an array) and use only
the first entry of the array

personal_information.each{|i| puts i[0]}

I hope this helps

Stefano

From: botp on 13 Jul 2010 04:56
On Tue, Jul 13, 2010 at 4:40 PM, Abder-rahman Ali
<abder.rahman.ali(a)gmail.com> wrote:
> What am I missing in the script?

the fun :)

> personal_information.each {|key| p key}
["Name", "Abder-Rahman Ali"]
["Age", "26"]

> personal_information.each {|key| p key.first}
"Name"
"Age"

> personal_information.each_key {|key| p key}
"Name"
"Age"

> personal_information.each_value {|key| p key}
"Abder-Rahman Ali"
"26"

> personal_information.each {|key,value| p key}
"Name"
"Age"

> personal_information.each {|key,value| p value}
"Abder-Rahman Ali"
"26"


kind regards -botp

From: Peter Hickman on 13 Jul 2010 05:01
If you want the keys only you can do this
"personal_information.keys.each do |key|" or
"personal_information.each_key do |key|"

This, however, "personal_information.each do |key|" returns each
element of the hash as an array in the form [key, value]

Look here for the documentation (
http://www.ruby-doc.org/core/classes/Hash.html ), in fact this should
be the first place you look when you have a problem.

From: Abder-Rahman Ali on 13 Jul 2010 05:21
Thanks a lot all for your replies. It really helps.
--
Posted via http://www.ruby-forum.com/.

 | 
Pages: 1
Prev: Cheap Wholesale Chanel Boots (free shipping)
Next: Why do I get undefined method?