Lesson 26 of 55
8 mins readPython Iterating Hashes: keys, values & each
In Plain English
The `keys %hash` function returns a list of all keys, `values %hash` returns all values, and `while (my ($k, $v) = each %hash)` iterates pairs efficiently.
Deep Dive: How It Works
keys %hash: Returns an array of keys (often sorted: `sort keys %hash`).
values %hash: Returns an array of corresponding values.
each %hash: Iterator yielding `($key, $value)` pairs one by one in a while loop.
Core Rules to Remember
keys %hash: Returns all keys as a list for iteration.
each %hash Iterator: Efficient for large hashes without building intermediate lists in memory.
Live Interactive Example
Hit Run Code to see it liveIterating Hash Keys and Pairs
Python 3.12
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Output Console
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How it works: sort keys %scores ordered the students alphabetically before lookup.
Your Turn: Micro Challenge
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Micro Exercise
Print Total Number of Keys
- Declare `%inventory = ( apples => 10, oranges => 5, berries => 20 );`
- Print `"Inventory categories: " . scalar(keys %inventory) . "\n"`.
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Sandbox Output
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