# K’th Non-repeating Character in Python using List Comprehension and OrderedDict

Given a string and a number k, find the k-th non-repeating character in the string. Consider a large input string with lacs of characters and a small character set. How to find the character by only doing only one traversal of input string?

Examples:

```Input : str = geeksforgeeks, k = 3
Output : r
First non-repeating character is f,
second is o and third is r.

Input : str = geeksforgeeks, k = 2
Output : o

Input : str = geeksforgeeks, k = 4
Output : Less than k non-repeating
characters in input.
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

This problem has existing solution please refer link. We can solve this problem quickly in python using List Comprehension and OrderedDict.

 `# Function to find k'th non repeating character  ` `# in string ` `from` `collections ``import` `OrderedDict ` ` `  `def` `kthRepeating(``input``,k): ` ` `  `    ``# OrderedDict returns a dictionary data  ` `        ``# structure having characters of input ` `    ``# string as keys in the same order they  ` `        ``# were inserted and 0 as their default value ` `    ``dict``=``OrderedDict.fromkeys(``input``,``0``) ` ` `  `    ``# now traverse input string to calculate ` `        ``# frequency of each character ` `    ``for` `ch ``in` `input``: ` `        ``dict``[ch]``+``=``1` ` `  `    ``# now extract list of all keys whose value ` `        ``# is 1 from dict Ordered Dictionary  ` `    ``nonRepeatDict ``=` `[key ``for` `(key,value) ``in` `\ ` `                    ``dict``.iteritems() ``if` `value``=``=``1``] ` `     `  `    ``# now return (k-1)th character from above list ` `    ``if` `len``(nonRepeatDict) < k: ` `        ``return` `'Less than k non``-``repeating \ ` `                ``characters ``in` `input``.' ` `    ``else``: ` `        ``return` `nonRepeatDict[k``-``1``] ` ` `  `# Driver function ` `if` `__name__ ``=``=` `"__main__"``: ` `    ``input` `=` `"geeksforgeeks"` `    ``k ``=` `3` `    ``print` `kthRepeating(``input``, k) `

Output:

```r
```

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