Group strings with values in Python

First, copy these two functions to be able to compute the argmax:

# given an iterable of pairs return the key corresponding to the greatest value
def argmax(pairs):
    return max(pairs, key=lambda x: x[1])[0]


# given an iterable of values return the index of the greatest value
def argmax_index(values):
    return argmax(enumerate(values))

Second, load the content of your CSV into a Python dictionary and proceed as follows:

from fuzzywuzzy import fuzz

input = {
    'GilletsJaunes': 100,
    'Macron': 50,
    'gilletsjaune': 20,
    'tax': 10,
}

threshold = 50

output = dict()
for query in input:
    references = list(output.keys()) # important: this is output.keys(), not input.keys()!
    scores = [fuzz.ratio(query, ref) for ref in references]
    if any(s > threshold for s in scores):
        best_reference = references[argmax_index(scores)]
        output[best_reference] += input[query]
    else:
        output[query] = input[query]

print(output)

{'GilletsJaunes': 120, 'Macron': 50, 'tax': 10}

This solves your problem. You can reduce your input sample by first converting your tags to lowercase. I'm not sure how fuzzywuzzy works, but I would suspect that "HeLlO" and "hello" and "HELLO" are always going to be greater than an 80, and they represent the same word.

import csv
from fuzzywuzzy import fuzz

data = dict()
output = dict()
tags = list()

with open('file.csv') as csvDataFile:
    csvReader = csv.reader(csvDataFile)
    for row in csvReader:
        data[row[0]] = row[1]
        tags.append(row[0])

for tag in tags:
    output[tag] = 0
    for key in data.keys():
        if fuzz.ratio(tag, key) > 80:
            output[tag] = output[tag] + data[key]