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K-th non-repeating character in Python using list comprehension and OrderedDict

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Examples:

 Input: str = pythonengineering, k = 3 Output: r First non-repeating character is f, second is o and third is r. Input: str = pythonengineering, k = 2 Output: o Input: str = pythonengineering, k = 4 Output: Less than k non-repeating characters in input. 

This problem has an existing solution, please refer to the List Comp Representation and

# Function for finding the kth non-repeating character
# in a line

from collections import OrderedDict

 

def kthRepeating ( input , k):

 

< code class = "comments"> # OrderedDict returns dictionary data

# structure with input characters

# string as keys in the same order as they are

# were inserted and 0 as default

dict = OrderedDict.fromkeys ( input , 0 )

 

# now go to the input line to calculate

  # frequency of each character

< p> for ch in input :

dict [ch] + = 1

 

# now retrieve a list of all keys whose value

  # 1 from the order dictionary

nonRepeatDict = [key for (key, value ) in

  dict . iteritems () if value = = 1 ]

 

# now returns the (k-1) th character from the list above

if len (nonRepeatDict) & lt; k:

return ’Less than k non - repeating

characters in input . ’

  else :

return nonRepeatDict [k - 1 ]

  
# Driver function

if __ name__ = = "__ main __"

input = "pythonengineering"

k = 3

print kthRepeating ( input , k)

Output:

 r 

This article courtesy of Shashank Mishra (Gullu) . If you are as Python.Engineering and would like to contribute, you can also write an article using contribute.python.engineering or by posting an article contribute @ python.engineering. See my article appearing on the Python.Engineering homepage and help other geeks.

Please post comments if you find anything wrong or if you’d like to share more information on the topic discussed above.

K-th non-repeating character in Python using list comprehension and OrderedDict Python functions: Questions

K-th non-repeating character in Python using list comprehension and OrderedDict repeat: Questions

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