From: Chuck Remes <cremes.devlist@...>
Date: 2008-08-08T10:36:14+09:00
Subject: Re: Most compact command for associate array 'totalling'?


On Aug 7, 2008, at 5:27 PM, Siep Korteling wrote:

> Chuck Remes wrote:
>> On Aug 7, 2008, at 4:59 PM, John Pritchard-williams wrote:
>>
>>>
>>> a["abc"]=a["abc"].to_i+1;
>>>
>>>
>>> But I"m sure there is a shorter way ? Better trick available here?
>>>
>>> As an aside to 'to_i' is to turn the 'nil' into zero: is this safe  
>>> to
>>> assume this?
>>>
>>> Thanks - sorry if this is stupid question....
>>
>> No stupid questions; they're all good.
>>
>> Here's a minor reworking of what you did to eliminate the #to_i.
>>
>> a = Hash.new { |h,k| h[k] = 0 }
>> a["abc"] += 1
>>
>> The special form of Hash.new that I used above will automatically
>> initialize the bucket to 0 for any new key it receives, so you avoid
>> the problem with nil and #to_i.
>>
>> cr
>
> a = Hash.new(0)
> a["abc"] += 1
>
> Has the same effect.

Quite true, but I find the block form to be a better "general case"  
form to know since it is so much more flexible. But that's just my  
preference.

cr