Array Question

["cybermalandro cybermalandro" <cybermalandro@xxxxxxxxx>]

So, I have an array that looks like this


rray(3) {
  [0]=>
  array(8) {
    ["line"]=>
    string(1) "1"
    ["ponbr"]=>
    string(5) "34474"
    ["emt"]=>
    string(3) "yes"
    ["qty"]=>
    string(1) "5"
    ["price"]=>
    string(2) "19"
    ["shipdate"]=>
    string(8) "11/06/07"
    ["tracking"]=>
    string(17) "11111111111111111"
    ["approved"]=>
    string(4) "true"
  }
  [1]=>
  array(8) {
    ["line"]=>
    string(1) "1"
    ["ponbr"]=>
    string(5) "TEST1"
    ["emt"]=>
    string(3) "yes"
    ["qty"]=>
    string(1) "5"
    ["price"]=>
    string(2) "19"
    ["shipdate"]=>
    string(8) "12/04/06"
    ["tracking"]=>
    string(9) "123123123"
    ["approved"]=>
    string(4) "true"
  }
  [2]=>
  array(8) {
    ["line"]=>
    string(1) "2"
    ["ponbr"]=>
    string(5) "TEST1"
    ["emt"]=>
    string(3) "yes"
    ["qty"]=>
    string(1) "5"
    ["price"]=>
    string(2) "12"
    ["shipdate"]=>
    string(8) "12/04/06"
    ["tracking"]=>
    string(12) "123123123123"
    ["approved"]=>
    string(4) "true"
  }
}


I want to see if the array["ponbr"]  values matched then pick this array and
construct another one with the matched arrays so I can get something like
this

  [0]=>
  array(8) {
    ["line"]=>
    string(1) "1"
    ["ponbr"]=>
    string(5) "TEST1"
    ["emt"]=>
    string(3) "yes"
    ["qty"]=>
    string(1) "5"
    ["price"]=>
    string(2) "19"
    ["shipdate"]=>
    string(8) "12/04/06"
    ["tracking"]=>
    string(9) "123123123"
    ["approved"]=>
    string(4) "true"
  }
  [1]=>
  array(8) {
    ["line"]=>
    string(1) "2"
    ["ponbr"]=>
    string(5) "TEST1"
    ["emt"]=>
    string(3) "yes"
    ["qty"]=>
    string(1) "5"
    ["price"]=>
    string(2) "12"
    ["shipdate"]=>
    string(8) "12/04/06"
    ["tracking"]=>
    string(12) "123123123123"
    ["approved"]=>
    string(4) "true"
  }

What is the best way to do this efficiently?

Thanks for your input!