Question

So i have an array, it has 1000 rows, and a column contains the age of a user, im trying to determine how to count the amount of rows for people who are <17, 17-25, 26-40 etc.

I know this is possible with a for loop:

for($i=0,$i<$totalrows,$i++)
    $birthdate=$array[$i][birthdate];
    if($birthdate>1995)
    {
        $seventeen=$seventeen+1;
    }
    elseif
    {
        etc...

but is there a built in function that can do this instead of needing to do a for loop to calculate all the values? Once the count got to millions wouldn’t this become quite taxing on the server?

edit/ should i be doing this with like 5 different SQL Selects? just using a count(*)? would that be more efficient?

Answer 1

You could use array_filter() and then count() the return values from that.

$seventeen = count(array_filter($array,
                                function ($entry) { 
                                    return ($entry['birthdate'] > 1995); 
                                }
                               )
                  )

N.B. Unless you have defined “birthdate” as a constant, you should quote it so that’s it’s treated as a string