Find Available Quantity From Dictionary

I have written a logic to find available quantity in location, for the location and quantity is managed with dictionary, d={'loc2': 500.0, 'loc3': 200.0, 'loc1': 1000.0, 'loc4': 1

Solution 1:

Could you explain why that output is unexpected? After one loc1 item has been appended to result, the value of qty will be 800. The line new_diff = abs(qty - item[1]) will return a minimal value (200) for the item loc1 again on the next iteration, so that item will be added to result once again. Once that's been done, qty will be -200, so the while loop will terminate. Should you only be adding items if their associated quantity is smaller than the variable qty? If so, you need more logic to do that - you could change the for loop to:

foritemin [x forxin new_list if x[1] <= qty]:

Solution 2:

This is what you would want:

d={'loc2': 500.0, 'loc3': 200.0, 'loc1': 1000.0, 'loc4': 100.0, 'loc5': 50.0}
from operator import itemgetter
deffind_combination(locs,qty):
    locs = sorted(d.items(),key=itemgetter(1),reverse=True) #get them in descending order
    result = []
    for loc,val in locs:
        if qty <= 0: #if we've reached the target qty then need to look no furtherbreakelif qty - val >= 0: #if we can take the val of a location and not go below zero do so
            qty -= val
            result.append((loc,val)) 
    return result 

Which when you

print find_combination(d,1800)
[('loc1', 1000.0), ('loc2', 500.0), ('loc3', 200.0), ('loc4', 100.0)]
>>>

Solution 3:

Does the following code do what you want? I have used the integer division to keep track of the remaining quantity.

deffind_combination(locations,qty): 
    new_list = sorted(locations.items(),key=lambda y: y[1],reverse=True)
    result = []
    for item in new_list:
        quotient = int(qty / item[1])
        result.extend(quotient*[item])
        qty -= quotient*item[1]
    return result

EDIT: Since you have used a check if item[0] not in result, I am assuming that you don't want to repeat any item in the result. In that case, HennyH's answer will work fine. This answer will not work. But if repetition is allowed, then this one would work.