array_sum vs a PHP foreach accumulator
A controlled aggregation test over the same deterministic integer list.
Question and test setup
How does PHP’s built-in array_sum compare with an explicit foreach loop for summing a medium integer list?
The built-in function may reduce interpreter-level loop overhead, while an explicit loop remains necessary when validation, filtering or overflow policy is part of the operation.
Built-ins can express intent clearly and execute optimized internal paths. Real aggregation code, however, often combines filtering, conversion and business rules.
Splitting one pass into several built-in calls can create extra arrays and erase an isolated advantage.
The measured gap
What this run shows: array_sum recorded the lowest median for this numeric array. The absolute saving should be multiplied by real call frequency before changing readable code. The slowest-to-fastest median spread was 356.25% on the measured host.
| Variant | Median | Middle 50% | Operations/s | Additional measure |
|---|---|---|---|---|
| array_sumFastest | 9.47 µs | 9.46 µs–9.90 µs | 105,580 | — |
| foreach accumulator | 43.21 µs | 41.56 µs–53.40 µs | 23,141 | — |
What the numbers suggest
Use the built-in result as evidence for the exact operation it represents. Do not decompose a richer single-pass transformation into multiple arrays solely to call array_sum.
When the task is exactly summation, the built-in is both concise and easy to review. When the loop already performs necessary validation, one pass may be the better whole-system design.
When the difference is worth acting on
- Use array_sum for a clean numeric list when summation is the complete operation.
- Keep validation and filtering explicit at trust boundaries.
- Measure allocation and total pipeline time when considering chained array functions.
Repetition and environment
- Both variants sum the same 5,000 deterministic integers.
- The explicit loop performs only accumulation so the semantic work matches array_sum.
- No filtering, type coercion policy or overflow handling is added.
Open measured environment
- Measurement run
- 2026-07-22T15:23:56+00:00
- PHP
- 8.4.23 (cli)
- Operating system
- Linux 4.18.0-553.85.1.el8_10.x86_64
- Architecture
- x86_64
- Processor
- AMD EPYC-Rome Processor
- Reported host memory
- 15.02 GiB host total
- CLI OPcache
- 0
- PHP memory limit
- 1024M
- Loaded study extensions
- json, openssl, zlib, mbstring, pdo_sqlite
- Timing clock
- hrtime(true)
- Measured rounds
- 7
Reasons the ranking may move
- Only integers are tested.
- Floating-point precision and mixed numeric strings are outside scope.
Primary documentation
These sources describe the PHP functions under test. The performance ranking comes only from this published fixture and environment.