def hamming_distance(name_A, name_B):
  count=0
  for i in range (len(name_A)):
    if name_A[i]!= name_B[i]:
      count +=1
  return count

   """ This function calculates and return the Hamming Distance between name_A and name_B"""

def name_distance(name_A, name_B):
  list1=list(name_A)
  list2=list(name_B)
  if len(name_A)>len(name_B):
    min_array = [] #holds all hamming distances
    diffs = 0 #the hamming distance at each iteration
    #loops through number of times comparisons should be made,
    for i in range (len(name_A)-len(name_B)+1):
      #compares the index of strings and record hamming distance
       for j in range (len(name_B)):
         if list1[j]!= list2[j]:
           diffs +=1
      #pops the first letter of string with longer length so that correct comparison can be made
       list1.pop(0)
       #adds the hamming distance to array
       min_array.append(diffs)
       #resets hamming distance
       diffs=0

  alength = len(name_A)
  blength = len(name_B)
  #gets the smallest hamming distance
  diffs = min(min_array)
  return diffs + alength - blength

  if len(name_B)>len(name_A):
    min_array = []
    diffs = 0
    for i in range (len(name_B)-len(name_A)+1):
       for j in range (len(name_A)):
         if list1[j]!= list2[j]:
           diffs +=1
       list1.pop(0)
       min_array.append(diffs)
       diffs=0
  alength = len(name_A)
  blength = len(name_B)
  diffs = min(min_array)
  return diffs + blength - alength

  """This function calculates and return the distance between name_A and name_B where these names may be different length. """

def get_name_lists(file_name):
    with open(file_name, 'r') as fr:
        return [name[:-1] for name in fr]

def name_matching(filename, target, k):
  ret_list = []#holding all the names that would be returned
  for i in get_name_lists(filename):#all the names from the textfile
    if name_distance(target,i) < k: #checking if the distance is less than k
      ret_list.append(i)# if it is, add it to the list returned
  return ret_list

  """This function loads in a list of names from a file, compares the target name to each name, and returns a list of all names within a distance of k from the target name"""