php根据特定键排序多维数组

Question

iam trying to sort this array by array[key]['premium']['Monthly'] and if there are two Monthly prices the same, then sort by quarterly, then semi-annual, then annual.

i search and couldnt figure out how to use array_multisort function.

Array (
[0] => Array (
    [product_id] => 1
    [rate] => 27.07
    [premium] => Array (
        [Annual] => 436.05
        [Semi-Annual] => 226.75
        [Quarterly] => 115.6
        [Monthly] => 37.11
    )
)
[1] => Array (
    [product_id] => 2
    [rate] => 35.00
    [premium] => Array (
        [Annual] => 565
        [Semi-Annual] => 293.8
        [Quarterly] => 149.73
        [Monthly] => 50.85
    )    
)
[2] => Array (
    [product_id] => 3
    [rate] => 30.52
    [premium] => Array (
        [Annual] => 497.8
        [Monthly] => 47.29
    )
)
)

Answer 1

I think you want to use usort function, something like

function compare($a, $b){
  $p1 = $a["premium"];
  $p2 = $b["premium"];
  if($p1["Monthly"] == $p2["Monthly"]){
     // compare by quarterly
     ...
  }else{
     if($p1["Monthly"] < $p2["Monthly"])then return -1;
     else return 1;
  }
}

usort($prices, "compare");

where $prices is your array. The comparision function isn't implemented fully, just to show the idea. Also, since it looks like there might be missing items in the price array (ie last one misses Quarterly and Semi-Annual) you have to check first (before comparison) does the items exists and take appropriate action in case one or both are missing.