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← Courses›Senior Deep-DivesModule 6 · FAANG-2026 deep dives›Walrus in comprehensions — scope leak gotchapredict112 / 161
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Task
📝 **Task:** Predict the exact output. \`data = ["py", "hello", "lambda", "ok"]\`. Two comprehensions filter by length, using walrus to bind \`n\` / \`m\`. Both finish — predict what \`n\` and \`m\` hold AFTER the comprehensions finish. Hint: walrus binds for every iteration, including filtered-out ones. 📋 Implement the function above. Tests run automatically. 💡 **Hint:** Re-read the theory if you get stuck.
Predict the output

Read the code carefully

data = ["py", "hello", "lambda", "ok"]

matches = [(s, n) for s in data if (n := len(s)) > 3]
print(matches)
print(f"n_after:{n}")

gen = ((s, m) for s in data if (m := len(s)) > 4)
print(list(gen))
print(f"m_after:{m}")

What will the program print? Write here:

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