Normalize Mobile Error Messages | Dataford Interview Questions

At Acme Mobile, different app layers emit inconsistent error strings for the same failure. Implement a reusable error normalization function that groups similar raw error messages under a canonical error key.

Task

Write a function group_errors(errors, rules) that takes a list of raw error strings and a list of normalization rules. Each rule is a pair [pattern, canonical]. For every error string, first normalize it by converting to lowercase and replacing every maximal sequence of digits with #. Then, if the normalized string contains one or more rule patterns, assign the error to the canonical value of the longest matching pattern. If no pattern matches, use the normalized string itself as the key. Return a dictionary mapping each final key to its frequency.

Constraints

1 <= len(errors) <= 10^4
0 <= len(rules) <= 10^3
1 <= len(error) <= 200
1 <= len(pattern), len(canonical) <= 200
If multiple rules match, choose the canonical value from the longest matching pattern

Function Signature

def group_errors(errors, rules):

Your question is Normalize Mobile Error Messages. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Task

Constraints

1 <= len(errors) <= 10^4
0 <= len(rules) <= 10^3
1 <= len(error) <= 200
1 <= len(pattern), len(canonical) <= 200
If multiple rules match, choose the canonical value from the longest matching pattern

Function Signature

def group_errors(errors, rules):

Your question is Normalize Mobile Error Messages. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.