Re: array.map! + delete_if possible ?

On 17.09.2011 00:03, Kassym Dorsel wrote:
> I have an array of strings that I need to modify. I either need to
> replace the string or delete the entry altogether.

irb(main):010:0> a = 10.times.to_a
=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
irb(main):011:0> a.map! {|i| i.odd? ? i : nil}.compact!
=> [1, 3, 5, 7, 9]
irb(main):012:0> a
=> [1, 3, 5, 7, 9]

> The only way I have
> been able to do this is :
>
>
> arr.delete("")
>
> (0..arr.size).each do |i|

arr.each_index do |i|

>    if arr[i].to_i == 1201
>      arr[i]=arr[i].to_s[8..-1].gsub(/"[^"]*"/,'::').gsub(/".*/,"::")

Maybe:

arr[i] = arr[i].to_s[8..-1].gsub(/"[^"]*(?:"|\z)/,'::')

Is this really what you want?  First you convert all quoted sequences to 
"::" and then you remove everything after the single remaining quote to 
the end by "::"?

>    else
>      arr[i-1] = arr[i-1] + arr[i].to_s[4..-1].to_s.gsub(/\s*/,"")

arr[i-1] << arr[i].to_s[4..-1].to_s.gsub(/\s*/,"")

>      arr[i]=nil
>    end
> end
>
> arr.delete(nil)

arr.compact!

> Is there a better way ?

First we should clarify what you are doing.  As far as I can see you 
want to iterate the array and either modify element i or convert element 
i and append it to element i - 1.  From this it is clear that you cannot 
use #map or #map! because those methods are intended to modify the 
current object.

> Also inside the else I get char 4->-1 of a string, but then need to
> explicitly change it into a string for gsub to work. Otherwise it gives
> me an undefined method 'gsub' for nilNilClass error.

So your statement that you have a String is not correct.  You are 
probably experiencing this effect

irb(main):017:0> s="123"
=> "123"
irb(main):018:0> s[4..-1]
=> nil

A bit of sample data would be helpful...

Kind regards

	robert