Word Frequency

Write a function that counts how many times each word appears in a string.

word_frequency(text)

Return a dict mapping each word to its count. Words are separated by single spaces.

Examples

word_frequency("a b a c b a")   // → {"a": 3, "b": 2, "c": 1}
word_frequency("x x x")          // → {"x": 3}

Walkthrough

Thinking it through

This is the exact counting pattern from the dictionaries lesson, applied directly:

def word_frequency(text):
    counts = {}
    for word in text.split():
        counts[word] = counts.get(word, 0) + 1
    return counts

text.split() gives you the individual words. For each one, counts.get(word, 0) looks up its current count — or 0, if this is the first time that word has shown up (since it isn't in counts yet, and .get() returns the default instead of raising KeyError). Adding 1 to that and assigning it back to counts[word] handles both cases uniformly: a brand-new word gets 0 + 1 = 1, and a word seen before gets incremented from whatever it already was.

This is exactly what collections.Counter does under the hood, from the previous section — here you're building the same logic by hand, which is worth doing once so the Counter shortcut isn't a black box.

main.py

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