Remove Vowels and Consonants | Dataford Interview Questions

Your question is Remove Vowels and Consonants. Start with the requirements on the right.

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Problem

Capital Group research workflows use compact text labels that may contain letters, digits, spaces, and punctuation. Implement a function that removes vowels, consonants, or both while preserving every retained character in its original order.

Formal Specification

Given an ASCII string s and two Boolean flags, return a new string:

Remove an ASCII vowel when remove_vowels is True. Vowels are a, e, i, o, and u, regardless of case.
Remove an ASCII consonant when remove_consonants is True.
Preserve letters that are not selected for removal.
Always preserve digits, whitespace, punctuation, and other non-ASCII characters.
The input string must not be modified. Return a string.

You may use a single left-to-right scan. Do not use regular expressions.

Constraints

0 <= len(s) <= 10^5
s may contain ASCII letters, digits, whitespace, punctuation, and Unicode characters
remove_vowels and remove_consonants are Boolean values
Preserve the relative order of all retained characters

Function Signature

def filter_letters(s, remove_vowels, remove_consonants):