Python loop not correctly looping

Question

My loop is "supposed" to go through the list from [0] to the final item which is at most [7] and then purchase and count how many times it purchased that item from the list and then multiply the result by a value.

What it is currently doing is purchasing a low number of items, outputting how many times each has been purchased and thats it. It isn't even "spending" all of its "allowance"

https://pastebin.com/vSecjxA5

and it generally outputs

CP Total: 2000
Type Item: Item
# of Properties: 5
{'MDEF': 4}
{'SPR': 3}
{'AGI': 2}
{'CRIT': 3}
{}

Which if you see the code and add the costs together it only adds up to 100-200 at most not anywhere near 2000

for aProp in S:
    cost = CostDic[aProp]
    if (cost * 5) < CP:
        purchase_ls = []
        while CP >= cost:
            b = randint(1, 5)
            cost = cost * b
            if CP < cost:
                continue
            purchase_ls.append(aProp)
            CP = CP - cost
    else:
        purchase_ls = []
        while CP >= cost:
            cost = cost
            if CP < cost:
                continue
            purchase_ls.append(aProp)
            CP = CP - cost
    print(dict(Counter(purchase_ls)))

Is the section in particular that is causing me grief

Answer 1

Here is your problem:

    while CP >= cost:
        b = randint(1, 5)
        cost = cost * b
        # More stuff follows...

In this loop you have now modified the value of cost , which I'm guessing you didn't mean to do. Specifically, in the line cost = cost * b I believe your intent was that cost on the right-hand side is representing the cost of an individual unit, and the cost on the left-hand side is representing the cost of "n" units, where "n" is a random number between 1 and 5.

But what this code is actually doing is different from that intention. The second time you enter that while loop, the variable cost is still at its new, higher value, and then will get multiplied again by a random number 1-5. So at this rate cost will quickly grow too large for CP >= cost to remain true.

I think what tripped you up here is that you used the same variable cost to represent different things at different times. I'd strongly suggest you change this into two different variables with more meaningful names, for example unitCost and groupCost , to prevent this type of confusion in the code later on.

Answer 2

For the loop in question, i have now modified it to

for aProp in S:
    cost = CostDic[aProp]
    if (cost * 5) < CP:
        purchase_ls = []
        while CP >= cost:
            b = randint(1, 5)
            mcost = cost*b
            if CP < mcost:
                continue
            purchase_ls.append(aProp)
            CP = CP - mcost
    else:
        purchase_ls = []
        while CP >= cost:
            if CP < cost:
                continue
            purchase_ls.append(aProp)
            CP = CP - cost
    print(dict(Counter(purchase_ls)))

Which does the looping part fine but it isn't doing 2 things correctly like i had hoped

1. It isn't adding the correct amount of append's to the list cause it is just adding 1 aProp when it is purchased in the top section of the loop it purchases b amount of them.
2. It doesn't cycle through the S list to purchase from. Its supposed to go from [0] to the final one (say it has 5 items) [4] and purchase them b times for each (unless it can only grab one) and then move on to the next one so, [0] rolls 3, gets purchased 3 times and moves to [1] which gets purchased 5 times, then moves on to... and finally hits [4] which gets purchased 2 times and then if it still has leftover CP it goes back through the list from [0]-[4] again.