[FIXED] Ranking objects by absolute occurrence

Issue

I have a list of dictionaries which contains contains floats. My goal is to rank these objects with considering the occurence the duplicates.

Example:

If the highest value is 19.93 and it occurs three times in the raw list, we will have three {"rank":1}'s, and as we already have 3 ranked items, the item with 19.07 value will have {"rank":4} as there are three above ranked objects. (This is the logic how european soccer score rankings are calculated. I want to achieve the same)

{'value': {'total': 19.93}, 'rank': 1}
{'value': {'total': 19.93}, 'rank': 1}
{'value': {'total': 19.93}, 'rank': 1}
{'value': {'total': 19.07}, 'rank': 4}
{'value': {'total': 18.24}, 'rank': 5}
{'value': {'total': 18.24}, 'rank': 5}
{'value': {'total': 18.24}, 'rank': 5}
{'value': {'total': 17.15}, 'rank': 8}
{'value': {'total': 16.8}, 'rank': 9}
{'value': {'total': 16.8}, 'rank': 9}
{'value': {'total': 16.8}, 'rank': 9}

But instead of the above, my code gives me:

{'value': {'total': 19.93}, 'rank': 1}
{'value': {'total': 19.93}, 'rank': 1}
{'value': {'total': 19.93}, 'rank': 1}
{'value': {'total': 18.24}, 'rank': 3}
{'value': {'total': 18.24}, 'rank': 3}
{'value': {'total': 18.24}, 'rank': 3}
{'value': {'total': 19.07}, 'rank': 4}
{'value': {'total': 17.15}, 'rank': 5}
{'value': {'total': 16.8}, 'rank': 6}
{'value': {'total': 16.8}, 'rank': 6}
{'value': {'total': 16.8}, 'rank': 6}

What I basically do is creating a unique list from the values, track the occurrence of the previous objects and add it to the current rank. I would really appreciate if somebody could show me what do I wrong as I feel I am really close.

#########################
# actual code 
import random

def rank_lista(ordered_list):
    vals = []
    # add all values into a list
    for list_item in ordered_list:
        try:
            vals.append(list_item['value']['total'])
        except Exception as e:
            print (e)

    
    unique_values = sorted(list(set(vals)))

    sorted_list = []
    for ooo in reversed(list(unique_values)):
        sorted_list.append(ooo)

    unique_values = []
    unique_values = sorted_list

    print ('sorted unique values:', unique_values)
    
    
    for ordered_list_item in ordered_list:
        try:
            val = ordered_list_item['value']['total']

            if unique_values.index(val) == 0:
                ordered_list_item['rank'] = unique_values.index(val)+1
            
            elif unique_values.index(val) == 1:
                previous_value_index = 0
                previous_value_count = vals.count(unique_values[previous_value_index])
                ordered_list_item['rank'] = 1 + previous_value_count
            else:
                previous_value_index = unique_values.index(val)-1
                previous_value_count = vals.count(unique_values[previous_value_index])
                ordered_list_item['rank'] = (previous_value_index + 1) + previous_value_count

        except Exception as e:
            print (e,2)



    return ordered_list


def create_random_list():
    unique_rounded_floats = list(set(round(random.uniform(1, 20), 2) for _ in range(9)))
    floats_with_duplicates = [item for sublist in [[float_] * 3 for float_ in unique_rounded_floats] for item in sublist]
    other_floats = [round(random.uniform(1, 20), 2) for _ in range(11)]
    result_array = floats_with_duplicates + other_floats

    arr = []
    for r in result_array:
        obj = {}
        obj['value'] = {'total':r}
        arr.append(obj)

    return arr

random_list = create_random_list()
print (random_list)

result_list = sorted(rank_lista(random_list), key=lambda d: float(d['rank']), reverse = False)   

for res in result_list:
    print (res)

Solution

You can use a simple loop, keeping track of the previous value and incrementing the rank if the value changes from an enumerate:

prev = None # this must be different from a number

# for each dictionary in descending order of values
for i, d in enumerate(sorted(random_list,
                key=lambda x: x['value']['total'],
                reverse=True), start=1):
    # if the value changes, update the rank
    if d['value']['total'] != prev:
        rank = i
    # assign the rank
    d['value']['rank'] = rank
    prev = d['value']['total']

Output:

[{'value': {'total': 19.93}, 'rank': 1},
 {'value': {'total': 19.93}, 'rank': 1},
 {'value': {'total': 19.93}, 'rank': 1},
 {'value': {'total': 19.07}, 'rank': 4},
 {'value': {'total': 18.24}, 'rank': 5},
 {'value': {'total': 18.24}, 'rank': 5},
 {'value': {'total': 18.24}, 'rank': 5},
 {'value': {'total': 17.15}, 'rank': 8},
 {'value': {'total': 16.8}, 'rank': 9},
 {'value': {'total': 16.8}, 'rank': 9},
 {'value': {'total': 16.8}, 'rank': 9}]

Answered By - mozway