python - To group number of data upto a certain limit

Question

If anyone could help me out to solve this?problem, that would be greatly appreciated. Here I have a list of weights (kg) of a few samples.

weight_list = [0.2, 0.4, 1.0, 0.7, 0.1, 0.4, 0.9, 0.1, 0.2, 0.4, 0.2, 0.1]

The maximum weight that could be for any sample is 1 kg.?I need to sum sample weights until the total mass is not exceeding 1 kg. For instance, this is what I expect after summing the weights of samples based on the given condition.?

grouped_list = [0.6, 1.0, 0.8, 0.4, 1.0, 0.9]

this is what I have so far, but it loops over infinitely.

weight_list = [0.2, 0.4, 1.0, 0.7, 0.1, 0.4, 0.9, 0.1, 0.2, 0.4, 0.2, 0.1]
grouped_list = []
for weight in weight_list:
    total = 0
    while total <= 1:
        total += weight
        if total > 1:
            total -= weight
            grouped_list.append(total)
            total = 0
        else:
            grouped_list.append(total)

I am open to entirely new methods as well, if there any module or easy way to group this, please kindly assist me.

Answer 1

This works, you are currently looping for the same weight everytime, instead, you should iterate the list like this:

weight_list = [0.2, 0.4, 1.0, 0.7, 0.1, 0.4, 0.9, 0.1, 0.2, 0.4, 0.2, 0.1]
grouped_list = []
total, count = 0, 0
# increment counter over the weight list
while count < len(weight_list):
    total += weight_list[count]
    if total > 1:
        # add the weight if it recently exceeded 1 by subtracting recent weight
        total -= weight_list[count]
        # round to 1 decimal point (due to floating point math)
        grouped_list.append(round(total, 1))
        total = 0
    else:
        count += 1
# add the left-over total if < 1
if total < 1:
    grouped_list.append(round(total, 1))
print(grouped_list)

gives

[0.6, 1.0, 0.8, 0.4, 1.0, 0.9]