From: Shadowfirebird <shadowfirebird@...>
Date: 2008-08-13T01:21:18+09:00
Subject: Re: What's the easiest way to check if param[:x][:y] exists?

Sorry, you're right:

irb(main):001:0> a = {:a=>{:x=>1}}
=> {:a=>{:x=>1}}
irb(main):003:0> p a[:a][:x]
1
=> nil
irb(main):004:0> p a[:a][:y]
nil
=> nil
irb(main):005:0> p a[:b][:x]
NoMethodError: undefined method `[]' for nil:NilClass
        from (irb):5

David's *much* smarter than me, so listen to him...


On Tue, Aug 12, 2008 at 5:18 PM, Shadowfirebird
<shadowfirebird@gmail.com> wrote:
> It looks to me as if you should be able to check for nil.
>
> foo( param[:x][:y] ) unless (param[:x][:y] == nil)
>
> On Tue, Aug 12, 2008 at 5:03 PM, Joshua Muheim <forum@josh.ch> wrote:
>> Hi all
>>
>> In PHP I can simply check whether $param['x']['y'] exists regardless
>> whether $param['x'] exists or not.
>> In Rails I get a NoMethodError when using
>>
>> if param[:x][:y]
>>  ..
>> end
>>
>> when param[:x] is nil. So I always have to use
>>
>> if param[:x] and param[:x][:y]
>>  ..
>> end
>>
>> but I think that's not very beautiful - think about a case where I have
>> to check whether param[:a][:b][:c][:d][:...] exists or not!
>>
>> Maybe there's a cooler way to do this? ;-)
>>
>> Thanks
>> Josh
>> --
>> Posted via http://www.ruby-forum.com/.
>>
>>
>
>
>
> --
> All you can do is try to know who your friends are as you head off to
> the war / Pick a star on the dark horizon and follow the light
>



-- 
All you can do is try to know who your friends are as you head off to
the war / Pick a star on the dark horizon and follow the light