PHP Benchmarks

Performance comparison of PHP code alternatives.

Test: array_merge vs. + (string keys)

Semantically, array_merge() and + are identical when the arrays contain string keys.

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Historical Results

Based on (6) saved test runs, The test labeled "array_merge()" was (on average) the faster by 0.0079 seconds, (0.933% faster)

array_merge() 100%
add operator 99.067%

The array_merge() test took 0.8373 seconds.
The add operator test took 0.8451 seconds.


Each test case ran 20 random code order iterations consisting of 205,897 loops for a total of 4,117,943 runs.

  • Line execution difference (0.000002) milliseconds.
  • Avg difference (0.000) milliseconds per 205,897 loops.
  • Total difference 7.88 milliseconds for 4,117,943 loops

The iteration variablity for Code 1 was (0.0000) milliseconds and Code 2 was (0.0000) milliseconds. The lower and the closer together there values are the more accurate the results are.


The first test, "array_merge()", was:

$array = array_merge($GLOBALS['dummy1'], $GLOBALS['dummy2'], $GLOBALS['dummy3']);

The second test, "add operator", was:

$array = $GLOBALS['dummy1'] + $GLOBALS['dummy2'] + $GLOBALS['dummy3'];

Running: Linux (x86_64:1 GB) PHP (