Change language

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

| |


 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)



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 or by posting an article contribute @ 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


Best laptop for Fortnite


Best laptop for Excel


Best laptop for Solidworks


Best laptop for Roblox


Best computer for crypto mining


Best laptop for Sims 4


Best laptop for Zoom


Best laptop for Minecraft


Latest questions


psycopg2: insert multiple rows with one query

12 answers


How to convert Nonetype to int or string?

12 answers


How to specify multiple return types using type-hints

12 answers


Javascript Error: IPython is not defined in JupyterLab

12 answers



Python OpenCV | cv2.putText () method

numpy.arctan2 () in Python

Python | os.path.realpath () method

Python OpenCV | () method

Python OpenCV cv2.cvtColor () method

Python - Move item to the end of the list

time.perf_counter () function in Python

Check if one list is a subset of another in Python

Python os.path.join () method