sol >> Write a function that will return the count of distinct case-insensitive alphabetic characters and numeric digits that occur more than once in the input string. The input string can be assumed to contain only alphabets (both uppercase and lowercase) and numeric digits.

duplicateCounter.py

#stepwise solution

def counter(word):
  numberList = []  # empty list for numbers
  alphaList = []  # empty list for alphabets
	
#sorting num and alpha from word into resp. list 
  for ch in word:
    if ch.isdigit():
      numberList.append(ch)
    elif ch.isalpha():
      alphaList.append(ch.lower())		#converting to lower case since matching is case-INsensitive
			
#counting and print only num/alpha occurring more than once
  for x in numberList:
    count = numberList.count(x)
      if count >1:
        print "{} --> {} ".format(x,count) 
      while numberList.count(x) > 1 :		#weeding tested num
        numberList.remove(x)
	
  for i in alphaList:
    count = alphaList.count(i)
    if count > 1:
      print" {} --> {}".format(i, count) 
    while alphaList.count(i) > 1: 		#weeding tested alpha
      alphaList.remove(i) 


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#"point-and-kill" solution

def counter(word):
  word = list(word.lower())  
  for i in word:
    if (i.isalpha()) or (i.isdigit()):
      count = word.count(i)
        if (count > 1):
          print "{} ={}" %(i,count) 
        while(word.count(i) > 1):
          word.remove(i)

that's all.... 
code attached...