Benchmark: python len vs cache

HTML Preparation code:

<script src='https://cdn.jsdelivr.net/pyodide/v0.26.3/full/pyodide.js'></script>

Script Preparation code:

async function globalMeasureThatScriptPrepareFunction() {
  	window.globalPyodide = await loadPyodide();
	await globalPyodide.runPython(`
		def test_len(n):
			arr = [0] * n
			for i in range(n):
				arr[i] = i
			return len(arr)

		def test_cache(n):
			arr = [0] * n
			l = 0
			for i in range(n):
				arr[i] = i
				l += 1
			return l

		def run(fct, n):
			for i in range(n):
				fct(n)
	`);    
}

Tests:

use len built-in
window.globalPyodide.runPython(` run(test_len, 1000) `);
use variable to cache size
window.globalPyodide.runPython(` run(test_cache, 1000) `);

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

use len built-in

22/s

use variable to cache size

12/s

Fastest: use len built-in (1.7x faster)

View exact numbers

✓ use len built-in: 22 ops/sec
• use variable to cache size: 12 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
use len built-in
use variable to cache size

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

use len built-in

22/s

use variable to cache size

12/s

View exact numbers

Test name	Executions per second
✓ use len built-in	22 Ops/sec
use variable to cache size	12 Ops/sec

python len vs cache (version: 2)

Comparing performance of: `use len built-in vs use variable to cache size`

Created: one year ago by: Registered User

Go to the latest result

use len built-in

use variable to cache size

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

python len vs cache (version: 2)

Comparing performance of: use len built-in vs use variable to cache size

Created: one year ago by: Registered User

Go to the latest result

use len built-in

use variable to cache size

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `use len built-in vs use variable to cache size`