compare 2 array contents in ruby

Question

I have a 2 arrays from 2 different locations, but they contain the same elements. Below shows what I have:

@var2 =  ["2/05/2008", "$1.5000", "$2.0000"]
         ["1/06/2007", "$1.4000", "$1.0000"] 

@var3 =  ["1/06/2007", "$1.4000", "$1.0000"]
         ["2/05/2008", "$1.5000", "$2.0000"]

And this is the code how I arrive at those arrays above..not a good ruby code I acknowledge it

 var1 = Nokogiri::HTML(open(file.htm))
 var1.xpath('//tr[position() > 1]').map do |row|
 @var2 = row.xpath('td').map(&:text)[0,3]
    puts @var2
 end

File.open('some.txt') do |file|
  file.each_line do |line|
    line1 = line.split(' ')
    line2 = line1[0]
    line3 = "$" + line1[1]
    line4 = "$" + line1[2]

    @var3 = line2.split(' ') + line3.split(' ') + line4.split(' ')
    puts @var3
  end
  file.close()
end

In both of these variables I have multiple rows like this. How can I compare @var2 and @var3? Also @var2 is in descending order of date. Is there a way to compare the values/contents of the two and get a result? This also means that with the above format if I change a value in one of the arrays then the comparison should fail, for example:

@var2 =  ["2/05/2008", "$1.5000", "$2.0000"]
         ["1/06/2007", "$1.4000", "$1.0000"]

@var3 =  ["1/06/2007", "$1.4456", "$1.0000"]
         ["2/05/2008", "$1.5000", "$2.2222"]

I have tried several ways but unfortunately its not worked. I think I need to loop into the arrays and compare, but not sure how to do it.

I have tried @var2 & @var3, @var2 - @var3. They don't seem to work if I change a value in one of the arrays. The comparison still seems to check for the index and says matches is found. I want a exact row by row comparison with the values in each array.

Also further information : -

I want to know if the array contains the exact same elements, the order doesn't matter.

There can be duplicates within both the arrays var2 and var3. The array sizes will be the same. there won't be less elements nor NIL's.

Half of your data given isn't in any variables, I assume they were meant to be nested arrays? — Andrew Marshall
– Andrew Marshall, Commented Mar 25, 2012 at 6:23
Also, your question is very unclear: do you want to know if the arrays contain the exact same elements, regardless of order? Or does order matter? Are all the elements unique? — Andrew Marshall
– Andrew Marshall, Commented Mar 25, 2012 at 6:29
@Andrew, yes sorry they are nested arrays. and want to know if the array contains the exact same elements, the order doesn't matter. — user1126946
– user1126946, Commented Mar 25, 2012 at 7:17

d11wtq · Accepted Answer · 2012-03-25 09:52:38Z

2

Sort the arrays before you compare them:

@var2.sort == @var3.sort

Unless I'm missing something, this is basically what the problem is.

answered Mar 25, 2012 at 9:52

d11wtq

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1 Comment

user1126946 Over a year ago

Hi, Thanks for the response. I have updated the original question. Please have a look. Thanks

Andrew Marshall · Accepted Answer · 2012-03-25 07:31:54Z

1

Compare their lengths with the length of their intersection:

@var2.length == @var3.length && @var2.length == (@var2 & @var3).length

edited Mar 25, 2012 at 7:31

answered Mar 25, 2012 at 7:29

Andrew Marshall

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4 Comments

Andrew Marshall Over a year ago

Thanks for the edit @Marc-AndréLafortune! Been coding for far too many hours straight and it's far too late and I thus I end up making silly mistakes like that :).

Marc-André Lafortune Over a year ago

Note that the solution assumes there are no duplicates.

user1126946 Over a year ago

Thanks Andrew. I think its going no where so here is the entire code and what I am doing. This aint great ruby code and I acknowledge it

user1126946 Over a year ago

var1 = Nokogiri::HTML(open('file.html))   var1.xpath('//tr[position() > 1]').map do |row|     @var2 = row.xpath('td').map(&:text)[0,3]     puts @var2.size   end    File.open('price.txt') do |file|     file.each_line do |line|       line1 = line.split(' ')       line2 = line1[0]       line3 = "$" + line1[1]       line4 = "$" + line1[2]        @var3 = line2.split(' ') + line3.split(' ') + line4.split(' ')       puts @var3.size     end     file.close()   end

Dogbert · Accepted Answer · 2012-03-25 05:13:01Z

0

How about

@var2.reverse == @var3

answered Mar 25, 2012 at 5:13

Dogbert

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8 Comments

user1126946 Over a year ago

Thanks, but this won't work mate. I want something where I'd be able to compare each and every value in the array "@var2 to @var3". So for example if I change a value in "@var3" from ["2/05/2008", "$1.5000", "$2.0000"] to ["2/05/2008", "$1.5000", "$2.22222"], then the comparison to "@var2" should be false and error out. Hope that helps

user1126946 Over a year ago

I want something where I'd be able to loop thru the values of the arrays

Dogbert Over a year ago

Did you try the code? It should compare every element of the array, and return false even if one thing doesn't match.

user1126946 Over a year ago

yep, and this is a smimple comparison I have

Dogbert Over a year ago

@user1126946 Can you post the code you used? That would clear things up.

|

Shiva · Accepted Answer · 2015-10-04 06:38:49Z

0

Using - operator of Array class

2.1.1 :006 > arr1 = [1,2,3,4]
=> [1, 2, 3, 4]
2.1.1 :007 > arr2 = [4,3,2,1]
=> [4, 3, 2, 1]
2.1.1 :008 > arr1-arr2
=> []
2.1.1 :009 >

So, you can do it like this

2.1.1 :001 > @var2 =  [["2/05/2008", "$1.5000", "$2.0000"],
2.1.1 :002 >              ["1/06/2007", "$1.4000", "$1.0000"] ]
 => [["2/05/2008", "$1.5000", "$2.0000"], ["1/06/2007", "$1.4000", "$1.0000"]] 
2.1.1 :003 > 
2.1.1 :004 >   @var3 =  [["1/06/2007", "$1.4000", "$1.0000"],
2.1.1 :005 >              ["2/05/2008", "$1.5000", "$2.0000"]]
 => [["1/06/2007", "$1.4000", "$1.0000"], ["2/05/2008", "$1.5000", "$2.0000"]] 
2.1.1 :006 > (@var2 - @var3) == []
 => true
2.1.1 :007 >

answered Oct 4, 2015 at 6:38

Shiva

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