Iterate through array and delete if match

ruby-talk
1

I'm trying to delete elements of an array if they match a string but my
code always leaves some matches and I think it's because it's having
trouble iterating through the same array it is trying to delete from, is
that true?

Here is the code:

@acl_all_array.each do |range|
     if range[/access-list/]
       @acl_all_array.delete(range)
       puts range
     end
  end

Is this the correct way to delete matched entries from an array?

Thanks

John

···

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

2

jackster the jackle wrote:

I'm trying to delete elements of an array if they match a string but my
code always leaves some matches and I think it's because it's having
trouble iterating through the same array it is trying to delete from, is
that true?

Here is the code:

@acl_all_array.each do |range|
     if range[/access-list/]
       @acl_all_array.delete(range)
       puts range
     end
  end

Is this the correct way to delete matched entries from an array?

Thanks

John

Use delete_if instead.

···

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RMagick: http://rmagick.rubyforge.org/

3

I believe there is a method on Array called delete_if for just such a case..
IIRC

/Shawn

···

On Fri, Oct 3, 2008 at 5:18 PM, Tim Hunter <TimHunter@nc.rr.com> wrote:

jackster the jackle wrote:

I'm trying to delete elements of an array if they match a string but my
code always leaves some matches and I think it's because it's having
trouble iterating through the same array it is trying to delete from, is
that true?

Here is the code:

@acl_all_array.each do |range|
    if range[/access-list/]
      @acl_all_array.delete(range)
      puts range
    end
end

Is this the correct way to delete matched entries from an array?

Thanks

John

Use delete_if instead.

--
RMagick: http://rmagick.rubyforge.org/

4

Tim Hunter wrote:

jackster the jackle wrote:

       puts range
     end
  end

Is this the correct way to delete matched entries from an array?

Thanks

John

Use delete_if instead.

Or Array#reject!

deleting while iterating with each is undefined behavior. It's like
sawing off the tree branch you are sitting on.

···

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

5

Or Array#reject!

deleting while iterating with each is undefined behavior. It's like
sawing off the tree branch you are sitting on.

hehehe...I know what you mean!

Tim's solution worked, I used:

@acl_all_array.each do |range|
     if range[/access-list/]
       @acl_range.push(range)
     end
  end
@acl_all_array.delete_if { |x| x[/access-list/] }

Thanks for all the help guys...I am going to read up on Array#reject! to
see how that might help me.

john

···

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

6

Hi --

Or Array#reject!

deleting while iterating with each is undefined behavior. It's like
sawing off the tree branch you are sitting on.

hehehe...I know what you mean!

Tim's solution worked, I used:

@acl_all_array.each do |range|
    if range[/access-list/]
      @acl_range.push(range)
    end
end
@acl_all_array.delete_if { |x| x[/access-list/] }

Thanks for all the help guys...I am going to read up on Array#reject! to
see how that might help me.

Check out Array#partition too. What you've got there looks like it
could be:

   @acl_all_array, @acl_range = @acl_all_array.partition do |range|
     range[/access-list/]
   end

or something like that.

David

···

On Sat, 4 Oct 2008, jackster the jackle wrote:

--
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   Intro to Ruby on Rails January 12-15 Fort Lauderdale, FL
   Advancing with Rails January 19-22 Fort Lauderdale, FL *
   * Co-taught with Patrick Ewing!
See http://www.rubypal.com for details and updates!

7

David A. Black wrote:

Hi --

Check out Array#partition too. What you've got there looks like it
could be:

   @acl_all_array, @acl_range = @acl_all_array.partition do |range|
     range[/access-list/]
   end

or something like that.

good call David.....I'm going to try and incorporate that into my code.
Nice to see you on the forum! I'm still mad that my training was never
approved :frowning:

john

···

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

8

And, to give you another option you can fill the second array inside the delete_if block as well:

@acl_all_array.delete_if { |x| x[/access-list/] and
   @acl_range.push(x)}

Cheers

  robert

···

On 04.10.2008 12:26, jackster the jackle wrote:

David A. Black wrote:

Hi --

Check out Array#partition too. What you've got there looks like it
could be:

   @acl_all_array, @acl_range = @acl_all_array.partition do |range|
     range[/access-list/]
   end

or something like that.