How can I sort array based on 'days left' in an ascending order? [duplicate]

bit confused on how to do this.

array:3 [▼
    0 => array:2 [▼
      "id" => 35
       "days_left" => "21"
     ]
     1 => array:2[▼
       "id" => 40
       "days_left" => "14"
     ]
     2 => array:2[▼
        "id" => 57
        "days_left" => "15"
     ]
]

I want the array to be ordered by ascending order based on the days left.

    $upcoming_b = [];
    foreach ($birthday as $key => $value){
        $day = Carbon::parse($value->birth_date);
        if(Carbon::now()->day <= $day->day){
            $upcoming_b[$key]['id'] = $value->id;
            $day_of_birth = $day->day;
            $today = Carbon::now()->day;
            $days_left = (int)$day_of_birth - (int)$today;
            $upcoming_b[$key]['days_left'] = $days_left;
        }
    }

via Chebli Mohamed