Find first non-repeating character Python

PROGRAM TO FIND FIRST NON-REPEATING CHARACTER IN A STRING IN ONE TRAVERSAL

NO_OF_CHARS = 256

  

# Returns an array of size 256 containg count

# of characters in the passed char array

def getCharCountArray(string):

    count = [0] * NO_OF_CHARS

    for i in string:

        count[ord(i)]+= 1

    return count

  

# The function returns index of first non-repeating

# character in a string. If all characters are repeating

# then returns -1

def firstNonRepeating(string):

    count = getCharCountArray(string)

    index = -1

    k = 0

  

    for i in string:

        if count[ord(i)] == 1:

            index = k

            break

        k += 1

  

    return index

  

# Driver program to test above function

string = "geeksforgeeks"

index = firstNonRepeating(string)

if index == 1:

    print "Either all characters are repeating or string is empty"

else:

    print "First non-repeating character is " + string[index]







OUTPUT

First non-repeating character is t

CREDITS: https://www.geeksforgeeks.org/given-a-string-find-its-first-non-repeating-character/