PHP：如果为空，如何调节max（array_filter）和min（array_filter）

Question

I have created an array using compact:

$rank_month = compact('jan','feb','mar'); Like this and the data will be fetch using queries and due to that the data will sometimes will be empty and the data will be numbers. And then I'm using the max(array_filter) and min(array_filter) to get the highest and lowest in the array but when the query is empty I get the

ERROR: max(): Array must contain at least one element

ERROR: Min(): Array must contain at least one element

is it possible to condition it like:

     if(empty(max(array_filter('$rank_month')))){
        $high = ""; }
    else{
    $high = max(array_filter('$rank_month'
}

or is their any way to fix this error? Even if the data is empty

Thanks.

Answer 1

You are passing array_filter a string when it actually wants an array . '$rank_month' is an 11-character string, it's not an array.

You want to make sure you pass the array to array_filter (as well as min and max ).

You also want to be checking the length of the filtered array before calling min / max .

$filtered_month = array_filter($rank_month);
if(!empty($filtered_month)){
    $high = max($filtered_month);
}
else{
    $high = '';
}

Answer 2

simply what the error says: $rank_month is an empty array use sizeof or count

if (sizeof($rank_month) > 1) {
    $high = max($rank_month);
} else {
   ...
}

Or

if (count($rank_month) > 1) {
     $high = max($rank_month);
 else {
  ...
}

Answer 3

You need to check if the Array is empty, not if the max value is empty. You also don't need to pass in array_filter , the array itself should work.

if(empty($rank_month)){
    $high = ""; 
} else {
    $high = max($rank_month);
}