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From: Sven S. on 5 Mar 2010 14:25
Hi

Cumbersome title, here's what I'd like to do both elegantly and without
monkey patching Hash:

Say, I need to pass a hash to a method:

mymethod :this => 'green'

Now I'd like to include a second hash member only if a condition is met:

mymethod :this => 'green, :that => ('blue' if condition)

This of course leaves ":that => nil" in the hash if the condition is not
met - which is no good, the key should just not be present at all. I
could delete_if after that, but isn't there a more elegant way?

Thanks for your ideas!
--
Posted via http://www.ruby-forum.com/.

From: Cory Chamblin on 5 Mar 2010 15:07
Jesús Gabriel y Galán wrote:
> One liner:
>
> mymethod(h = {:this => 'green'} && condition ? h.merge({:that =>
> 'blue'}) : h)
>

You could also do it this way:

method {:Apples => 1}.merge(condition ? {:Oranges => 2} : {})
--
Posted via http://www.ruby-forum.com/.

From: Michael Fellinger on 5 Mar 2010 15:14
On Sat, Mar 6, 2010 at 4:25 AM, Sven S. <svoop(a)delirium.ch> wrote:
> Hi
>
> Cumbersome title, here's what I'd like to do both elegantly and without
> monkey patching Hash:
>
> Say, I need to pass a hash to a method:
>
> mymethod :this => 'green'
>
> Now I'd like to include a second hash member only if a condition is met:
>
> mymethod :this => 'green, :that => ('blue' if condition)
>
> This of course leaves ":that => nil" in the hash if the condition is not
> met - which is no good, the key should just not be present at all. I
> could delete_if after that, but isn't there a more elegant way?

p({this: 'green'}.merge(1 == 2 ? {that: 'blue'} : {}))
{:this=>"green"}

p({this: 'green'}.merge(1 == 1 ? {that: 'blue'} : {}))
{:this=>"green", :that=>"blue"}


> Thanks for your ideas!
> --
> Posted via http://www.ruby-forum.com/.
>
>



--
Michael Fellinger
CTO, The Rubyists, LLC

From: Jesús Gabriel y Galán on 5 Mar 2010 15:00
On Fri, Mar 5, 2010 at 8:25 PM, Sven S. <svoop(a)delirium.ch> wrote:
> Hi
>
> Cumbersome title, here's what I'd like to do both elegantly and without
> monkey patching Hash:
>
> Say, I need to pass a hash to a method:
>
> mymethod :this => 'green'
>
> Now I'd like to include a second hash member only if a condition is met:
>
> mymethod :this => 'green, :that => ('blue' if condition)
>
> This of course leaves ":that => nil" in the hash if the condition is not
> met - which is no good, the key should just not be present at all. I
> could delete_if after that, but isn't there a more elegant way?

I'm not sure I understand. You want too add :that => 'blue' to the
hash only if condition?

h = {:this => 'green'}
h[:that] = 'blue' if condition
mymethod h

One liner:

mymethod(h = {:this => 'green'} && condition ? h.merge({:that => 'blue'}) : h)

A bit ugly, in my opinion. I like my first way better.

Jesus.

From: Nick Brown on 5 Mar 2010 16:36
>>> mymethod(h = {:this => 'green'} && condition ? h.merge({:that =>
>>> 'blue'}) : h)
>>
>> You could also do it this way:
>>
>> method {:Apples => 1}.merge(condition ? {:Oranges => 2} : {})


For the love of all that is good and holy, please do not try to cram two
elegant lines of code into one disgusting line. That way lies madness...

;-)
--
Posted via http://www.ruby-forum.com/.

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