Letter frequencies

Return a dictionary that tells you how many times each character appears in a string. For "aab" that is {"a": 2, "b": 1}.

The handy move is freq.get(ch, 0) — it reads the current count for ch, or 0 if you haven't seen it yet. Add 1 and store it back.

Write char_frequency(s) that returns a dictionary mapping each character in s to the number of times it appears.

def char_frequency(s):
    # map each character to how many times it appears
    return {}

Click Run to see the output here.

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