Update edit distance.py

Author: je-suis-tm

edit distance.py

@@ -48,11 +48,11 @@
 #the cumulated steps we have taken should be matrix[m-1][n]+1
 #for replacement, it is a lil bit tricky
 #there are two scenarios
-#if len(a)==len(b)
+#if a[m]==b[n]
 #it should be matrix[m-1][n-1]
-#we are replacing mth letter of string a with nth letter of string b
-#the process is simultaneous
+#we dont need any replacement at all
 #else, it should be matrix[m-1][n-1]+1
+#we replace mth letter of string a with nth letter of string b
 #after we managed to understand three different approaches
 #we want to take the minimum steps among these three approaches
 #throughout the iteration of different positions of both strings
@@ -61,16 +61,23 @@ def edit(a,b):
  len_a=len(a)
  len_b=len(b)
 
+ #this part is to create a matrix of len(a)*len(b)
+ #as lists start at index 0
+ #we get a matrix of (len(a)+1)*(len(b)+1) instead
  c=[]
  for i in range(len_a+1):
  c.append([0]*(len_b+1))
- 
  for j in range(len_a+1):
  c[j][0]=j
- 
  for k in range(len_b+1):
  c[0][k]=k
- 
+ 
+ #we take iterations on both string a and b
+ #next, we check if a[m]==b[n]
+ #if yes, no replacement needed
+ #if no, replacement needed
+ #we take a minimum functions to see which combinations would give the minimum steps
+ #eventually we got what we are after
  for l in range(1,len_a+1):
  for m in range(len_b+1):
  if a[l-1]==b[m-1]:
@@ -80,10 +87,9 @@ def edit(a,b):
 
  return c[len_a][len_b]
 
+#lets get some random strings to test
 import random as rd
-
-
- 
+ 
 temp=rd.randint(1,20)
 temp1=rd.randint(1,20)
 alphabet='abcdefghijklmnopqrstuvwxyz'