How can we iteratively create sublists from a list based on a sum threshold?

[member 428835]

Hello PF!

Initializing with an empty list [], how would we perform the operations [[1]] and then [[1,2]] then [[1,2,3]] then [[1,2,3],[2]] then [[1,2,3], [2,4]] then [[1,2,3],[2,4],[1]] and so on. I'm trying to do this iteratively, so within a for-loop. Basically, given a list of numbers [1,2,3,2,4,1] add them to a sublist until the sum of values of that sublist exceeds a threshold, in which case create a new sublist. I've no clue how to do this, and have googled but to no avail

 

[jack action]

You didn't specified a language, but in PHP:

<?php
function makeList($numbers, $threshold){
    $list = [];
    $sublist = [];
    $total = 0;

    foreach($numbers as $number){
        $sublist[] = $number;
        $total += $number;
    
        if($total > $threshold){
            $list[] = $sublist;
            $total = 0;
            $sublist = [];       
        }
    }

    if(!empty($sublist)){
        $list[] = $sublist;
    }
    
    return $list;
}

$numbers = [1,2,3,2,4,1];
$threshold = 5;

var_dump(makeList($numbers, $threshold));

Output:

array(3) {
  [0]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(2)
    [2]=>
    int(3)
  }
  [1]=>
  array(2) {
    [0]=>
    int(2)
    [1]=>
    int(4)
  }
  [2]=>
  array(1) {
    [0]=>
    int(1)
  }
}

 

[Mark44]

You didn't specified a language

It's in the thread title -- Python.

 

[jack action]

It's in the thread title -- Python.

Then it will be left as an exercise for the OP to convert it!

 

[jedishrfu]

Then it will be left as an exercise for the OP to convert it!

I wonder how many teachers have gotten that response from their students.

 

[member 428835]

Got it, thanks for the suggestion!