Question

I have 2 arrays. One would be the original data, the other would be the new data. Between the 2 of them there could be matching values. And I need to figure out from the new inbound array what’s new, what’s a match, and what’s not a match.

The end goal is that I need these 3 arrays, one of items removed from the original, one of items that are new entries, and then the original entries that matched anything in the new entries.

I was thinking something to the extent of starting off with 3 blank arrays to fill as I cycle over the original or new with a loop and compare them adding each type old, new, removing to there respective array so I can work with the results there after. Which I can piece together an idea in my head that works for 2 arrays as the output, but the 3rd I get lost on. So Im kinda hindged on this bit for the moment. looking for advice and or help Creating a loop or something better that will yield the 3 sets of results I am looking for.

Array of original data from database:

Array(
      15,
      22,
      100,
      1500,
      2000,
      500,
      3000,
      1101
   )

Array of inbound new data

Array(
      100,
      800,
      920,
      1500,
      2000,
      1603,
      500,
      3000,
      1101
   )

Array of expected matches between original and inbound new:

Array(
      100,
      1500,
      2000,
      500,
      3000,
      1101
   )

Array of expected “new” entries between original and new:

Array(
      100,
      800,
      920,
      1603
   )

Array of expected entries from old that don’t match between original and new:

Array(
      15,
      22
   )

It may not be spot on as I obviously just hand typed these.. but hopefully it demonstrates what Im trying to achieve to some extent

Answer 1

Barmar’s comment is correct, array_diff and array_intersect are what you want. You have a typo in your question though, “100” appears in both the matches and the new values arrays.

<?php
$orig = array(15, 22, 100, 1500, 2000, 500, 3000, 1101);
$post = array(100, 800, 920, 1500, 2000, 1603, 500, 3000, 1101);

// Gets things in both arrays
$matches = array_intersect($orig, $post);
// Gets things in $post that aren't in $orig
$new     = array_diff($post, $orig);
// Gets things in $orig that aren't in $post
$removed = array_diff($orig, $post);

foreach (array($orig, $post, $matches, $new, $removed) as $array) {
    print_r($array);
}

My guess… you’re processing checkboxes or multi-selects to determine what to keep, what to add and what to remove.