Exercise 3: Count Occurrences with a While Loop — Possible Solution
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fruits = ["apple", "pear", "apple", "banana", "pear", "apple"]

counts = {}
index = 0

while index < len(fruits):
    fruit = fruits[index]
    if fruit in counts:
        counts[fruit] += 1
    else:
        counts[fruit] = 1
    index += 1

print(counts)

Output:
{'apple': 3, 'pear': 2, 'banana': 1}

WHY THIS WORKS AS AN ANSWER
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The "if fruit in counts" check is doing the real work: it distinguishes
"I've seen this fruit before, so add one to its existing count" from
"this is the first time, so start its count at 1." Without that check,
counts[fruit] += 1 on a brand-new key would raise a KeyError, since you
can't add 1 to a value that doesn't exist yet.

The while loop itself is the simplest shape in this whole exercise set —
a single index walking a single list, no nested search required —
because "does this key exist" is answered directly by the dictionary's
own "in" operator rather than a manual scan, unlike searching a list or
tuple for a value in the earlier exercises.