Filter a List of Names

MediumPython

Problem

Stripe Dashboard search may need to filter a list of connected account or customer names while users type a query. Implement a function that performs flexible, case-insensitive name matching without changing the original display values.

A name matches when every query token appears as a substring of at least one token in the name. Matching must ignore case, punctuation, and repeated whitespace. Return matching names in their original order, including duplicates. If the query contains no searchable tokens, return all names.

Formal Specification

Implement filter_names(names, query):

names is a list of strings.
query is a string.
Return a new list containing the original name strings that match the query.
Tokenize text into consecutive alphanumeric sequences after case folding. For example, "Acme_Payments" becomes ['acme', 'payments'].
A query token can match any name token by substring.

Constraints

0 <= len(names) <= 10^4
Each name contains at most 100 characters
query contains at most 100 characters
Names may contain Unicode letters, digits, spaces, and punctuation

Function Signature

def filter_names(names, query):

Formal Specification

Implement filter_names(names, query):

names is a list of strings.
query is a string.
Return a new list containing the original name strings that match the query.
Tokenize text into consecutive alphanumeric sequences after case folding. For example, "Acme_Payments" becomes ['acme', 'payments'].
A query token can match any name token by substring.