Clean up code, and add comments

fill.py

 #!/bin/env python3
 
-listes = ["", "che", "com", "fii", "hur", "iik", "ani", "lab", "ove"]
-nbListes = len(listes)-1
+"""
+This script transforms votes in number form into votes in mathematical form.
+For example, given five candidates A, B, C, D, E, and two ballots 12345 and 11222, our output should be "A > B > C > D > E" for the first ballot, and "A = B > C = D = E" for the second ballot.
+Input votes should be stored in number form in the file `results_bruts.txt`, one vote per line.
+Votes in mathematical form will be written to the file `results_out.txt`, one vote per line.
+"""
 
-with open('results.txt','r') as data:
-    o = open('results_out.txt','w')
+candidates = ["che", "com", "fii", "hur", "iik", "ani", "lab", "ove"]
+nbCandidates = len(candidates)
+# For example, with 8 candidates, the max rank a candidate can be given is 9 (no rank given => below every other rank).
+maxRankPossible = nbCandidates + 1
+
+with open("results_bruts.txt", "r") as data:
+    o = open("results_out.txt", "w")
+    # * Read raw data. One line = one vote. Each line is a string with exactly nbCandidates = 8 numbers, each number is in [1, maxRankPossible].
     for line in data.readlines():
-        maxColumn = int(max(line))
-        for column in range(1,10):
+        # Store the highest rank for this vote, so that we know when we need to stop putting ">" at the end.
+        maxRank = int(max(line))
+        # * For each rank possible, we are going to check if one or several candidates has been given that rank.
+        for rank in range(1, maxRankPossible + 1):
             first = True
             found = False
-            for ind in range(0,nbListes):
-                if int(line[ind]) != column:
+            # Check all candidates.
+            for ind in range(0, nbCandidates):
+                # If the rank given to that candidate isn't equal to the rank that we are currently checking, do nothing.
+                if int(line[ind]) != rank:
                     continue
+                # If another candidate has already been given that rank
                 if not first:
                     o.write(" = ")
-                o.write(listes[ind+1])
+                o.write(candidates[ind])
                 first = False
                 found = True
-            if found and column < maxColumn:
+            if found and rank < maxRank:
                 o.write(" > ")
         o.write("\n")
     o.close()