Count Item Frequencieseasy

Count Item Frequencies

easy Python for AI 10–15 min

NumPy allowed · plain Python earns 10 bonus points

Implement an element frequency counter using standard Python dictionaries -- the primary foundation for word frequency analysis, token counting, and categorical distribution calculation in machine learning.

Related Skills

Language Fundamentals

Task

Implement count_frequencies(items): return a dictionary mapping each distinct item in items to the number of times it appears. If items is empty, return an empty dictionary {}.

Function Signature

count_frequencies(items: list) -> dict

Examples

Example 1: String Items
Input: items = ['apple', 'banana', 'apple', 'orange', 'banana', 'apple']
Output: {'apple': 3, 'banana': 2, 'orange': 1}

Example 2: Integer Items
Input: items = [1, 2, 2, 3, 3, 3]
Output: {'1': 1, '2': 2, '3': 3}

Constraints

Libraries are allowed; a plain-Python solution earns 10 bonus points.
Must handle empty input list by returning an empty dict {}.
Preserves types of the items (strings, integers, etc.) as dictionary keys.

Python3Saved ✓

def count_frequencies(items: list) -> dict:

"""Count the frequency of each element in the input list.

Return a dictionary mapping each unique item to its count.

An empty list should return an empty dictionary."""

# Your implementation here

pass

Case 1: String Items

Input: items = ['apple', 'banana', 'apple', 'orange', 'banana', 'apple']

Expected: {'apple': 3, 'banana': 2, 'orange': 1}

Case 2: Integer Items

Input: items = [1, 2, 2, 3, 3, 3]

Expected: {'1': 1, '2': 2, '3': 3}