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

• Python
• member 428835
In summary, the conversation was about how to perform operations on a list of numbers and create sublists based on a given threshold. A possible solution using PHP was provided, but the language can be converted to Python as an exercise for the original poster.
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

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

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:

Code:
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)
}
}

jack action said:
You didn't specified a language
It's in the thread title -- Python.

jack action
Mark44 said:
It's in the thread title -- Python.
Then it will be left as an exercise for the OP to convert it!

jedishrfu
jack action said:
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.

jack action
Got it, thanks for the suggestion!

## 1. How do I create a sublist from a list in Python?

To create a sublist from a list in Python, you can use the slice operator [ ] or the slice function. The syntax for creating a sublist using the slice operator is list_name[start_index:end_index], where the start_index is the index of the first element you want to include and the end_index is the index of the element after the last element you want to include. The syntax for creating a sublist using the slice function is slice(start_index, end_index).

## 2. Can I create a sublist from a list in other programming languages?

Yes, you can create a sublist from a list in other programming languages such as Java, C++, and JavaScript. Each language may have different syntax and methods for creating a sublist, but the concept is the same. You can use the slice operator or a similar function to specify the start and end index of the sublist.

## 3. How can I create a sublist with specific elements from a list?

To create a sublist with specific elements from a list, you can use the slice operator or the slice function and specify the indices of the elements you want to include. For example, if you have a list of numbers and you only want to include the first three elements in the sublist, you can use the syntax list_name[0:3] or slice(0,3). This will create a sublist with the first three elements of the original list.

## 4. Can I create a sublist with elements from a list that meet certain criteria?

Yes, you can create a sublist with elements from a list that meet certain criteria by using conditional statements or filter functions. For example, if you have a list of numbers and you only want to include the even numbers in the sublist, you can use a conditional statement or the filter function to only include elements that are divisible by 2.

## 5. What is the benefit of creating a sublist from a list?

The benefit of creating a sublist from a list is that it allows you to manipulate and work with a smaller portion of the original list, making it easier to perform specific tasks or operations. It can also help with organizing and structuring data in a more manageable way.

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