Comparing contents of two huge arrays 
November 6th, 2008, 02:00 PM
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Posts: 82
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Hi,
I have two very huge arrays, the second array contains some of the elements of array1 and also different elements, both are not of the same size, have to find only the elements that are not common in both the arrays, I used array_diff but its not working can some body help me with this??
Thanks in advance
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November 6th, 2008, 02:22 PM
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Posts: 4,862
Provided Answers: 9 | | | re: Comparing contents of two huge arrays
Post the code you have tried. Use code tags.
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November 6th, 2008, 02:33 PM
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Posts: 82
| | | re: Comparing contents of two huge arrays
- <?
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$array1=array("++Hello how are you 20000901",
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"++Hows work 20010201",
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"++Am doing great 30089254");
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$array2=array("-+Hows work 20010201",
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"-+I like PHP 2657656",
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"-+Am doing great 30089254");
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$arry3=array_diff($array1,$array2);
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print_r($arry3);
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?>
the output should display just first element of array1 i.e ++Hello how are you 20000901
here am just giving a part of the input the actual input has more elements of similar format.
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November 6th, 2008, 03:28 PM
|  | Expert | | Join Date: Mar 2007 Location: England
Posts: 1,064
Provided Answers: 2 | | | re: Comparing contents of two huge arrays
The array elements all differ
[PHP]"++Hello how are you 20000901",
"++Hows work 20010201",
"++Am doing great 30089254");
"-+Hows work 20010201",
"-+I like PHP 2657656",
"-+Am doing great 30089254");[/PHP]
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November 7th, 2008, 04:03 AM
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Posts: 82
| | | re: Comparing contents of two huge arrays
Actually I have remove that -+ and ++ and then compare but how do I remove that??
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November 7th, 2008, 10:36 AM
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Posts: 1,064
Provided Answers: 2 | | | re: Comparing contents of two huge arrays
Quote: |
but how do I remove -+ and ++
| You will have to use string functions to remove.
str_replace is a simple method [PHP]$remove = array('++','-+');
str_replace($remove,'',$array);[/PHP]However this means looping through every array element before doing the array_diff.
You could use one of the array functions that employ a callback function
or array_walk().
Is it not better to strip the operator symbols off the string before inserting in the array?
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November 8th, 2008, 04:51 PM
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Posts: 82
| | | re: Comparing contents of two huge arrays
It is not possible to remove the -+ and ++ before inserting into the array. But how do I use the array_walk?is it possible the function in array_walk to return a value??
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November 8th, 2008, 05:44 PM
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Posts: 82
| | | re: Comparing contents of two huge arrays
Can I create a singly linked list for comparing the arrays?If yes how to do it??
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November 9th, 2008, 01:47 PM
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Posts: 82
| | | re: Comparing contents of two huge arrays
I used the following code to display only non duplicate elements but am not getting the required results can you plz tell me the problem with this code here?? - $rep=array("-+");
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foreach($array1 as $array) {
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$x=str_replace($rep,"",$array);
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array_push($a,$array);
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}
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$repl=array("++");
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foreach($array2 as $array) {
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$y=str_replace($repl,"",$array);
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array_push($b,$array);
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}
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$c=array_merge($a,$b);
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$d=array_unique($c);
Last edited by pbmods; November 9th, 2008 at 02:31 PM.
Reason: Added CODE tags.
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