3v4l.org

run code in 300+ PHP versions simultaneously
<?php class Reference { private static $DATA = []; private $index = 0; public function __construct($value) { // cannot create a reference of a reference if ($value instanceof self) { $this->index = $value->index; } else { $this->index = count(self::$DATA); self::$DATA[$this->index] = $value; } } public function get() { return self::$DATA[$this->index]; } public function set($value) { self::$DATA[$this->index] = $value; } } $x = [1, 2, 3]; // foreach($x as &$ref) { ... } /* $x[0] */ $x[0] = new Reference($x[0]); // Reference#0(index 0) = 1 $ref = clone $x[0]; // Reference#1(index 0) $ref->set($ref->get() + 100); // set index 0 = 101 /* $x[1] */ $x[1] = new Reference($x[1]); // Reference#2(index 1) = 2 $ref = clone $x[1]; // Reference#3(index 1) $x[0] = $x[0]->get(); // without $ref, $x[0] is the only reference to its value and demoted back to a value $ref->set($ref->get() + 100); // set index 1 = 101 /* $x[2] */ $x[2] = new Reference($x[2]); // Reference#4(index 2) = 3 $ref = clone $x[2]; // Reference#5(index 2) $x[1] = $x[1]->get(); // demoted $ref->set($ref->get() + 100); // set index 2 = 103 // end foreach /* $x is [101, 102, Reference#4(index 2)] */ /* $ref remains as Reference#5(index 2) */ $b = $x; // $b[0] = clone $x[0]; - except $x[0] is an integer so this was automatic // $b[1] = clone $x[1]; - same $b[2] = clone $x[2]; // creating a copy of what was in $x[2] /* $b is [101, 102, Reference#6(index 2)] - a different Reference as $x[2] and $ref but the same underlying value */ $b[0] = 0; // foreach($x as &$ref) { ... } /* $x[0] */ $x[0] = new Reference($x[0]); // Reference#7(index 3) = 101 $ref = clone $x[0]; // Reference#8(index 3) $ref->set($ref->get() + 100); // set index 3 = 201 /* $x[1] */ $x[1] = new Reference($x[1]); // Reference#9(index 4) = 102 $ref = clone $x[1]; // Reference#10(index 4) $x[0] = $x[0]->get(); // demoted $ref->set($ref->get() + 100); // set index 4 = 202 /* $x[2] */ // $x[2] = new Reference($x[2]); // - except $x[2] is already Reference#4(index 2) $ref = clone $x[2]; // Reference#11(index 2) $x[1] = $x[1]->get(); // demoted $ref->set($ref->get() + 100); // set index 2 = 203 // end foreach /* $x is [201, 202, Reference#4(index 2)] */ /* $ref remains as Reference#11(index 2) */ /* $b was not modified during the foreach and still contains [0, 102, Reference#6(index 2)] */ /* however the underlying value of the Reference did change */ // var_dump($b); var_dump([$b[0], $b[1], $b[2]->get()]);

Here you find the average performance (time & memory) of each version. A grayed out version indicates it didn't complete successfully (based on exit-code).

VersionSystem time (s)User time (s)Memory (MiB)
8.4.120.0050.00425.93
8.4.110.0100.00622.46
8.4.100.0100.01119.04
8.4.90.0130.00718.68
8.4.80.0080.01120.51
8.4.70.0110.01017.86
8.4.60.0090.00818.79
8.4.50.0050.00418.91
8.4.40.0030.01319.27
8.4.30.0190.00017.73
8.4.20.0130.00717.85
8.4.10.0060.00317.66
8.3.250.0130.00719.00
8.3.240.0120.00817.20
8.3.230.0090.01016.60
8.3.220.0110.00719.10
8.3.210.0090.00916.72
8.3.200.0050.00416.57
8.3.190.0080.01017.09
8.3.180.0090.00419.29
8.3.170.0060.01218.96
8.3.160.0090.00917.02
8.3.150.0120.00617.19
8.3.140.0000.01117.44
8.3.130.0080.00018.52
8.3.120.0040.01418.72
8.3.110.0070.01020.94
8.3.100.0040.00424.06
8.3.90.0090.00626.77
8.3.80.0060.00617.97
8.3.70.0060.00916.63
8.3.60.0090.01216.88
8.3.50.0080.01221.93
8.3.40.0140.00718.97
8.3.30.0140.00018.84
8.3.20.0080.00019.46
8.3.10.0040.00421.89
8.3.00.0040.00419.08
8.2.290.0100.00920.62
8.2.280.0090.00820.13
8.2.270.0100.01016.39
8.2.260.0030.00618.97
8.2.250.0050.00318.23
8.2.240.0060.00318.89
8.2.230.0040.00422.58
8.2.220.0030.00537.54
8.2.210.0070.00026.77
8.2.200.0030.00618.10
8.2.190.0160.00318.62
8.2.180.0100.00618.16
8.2.170.0070.00722.96
8.2.160.0120.00321.99
8.2.150.0000.00824.18
8.2.140.0050.00224.66
8.2.130.0030.00718.04
8.2.120.0080.00026.35
8.2.110.0150.00621.18
8.2.100.0120.00018.03
8.2.90.0000.00819.14
8.2.80.0000.00817.97
8.2.70.0040.00417.50
8.2.60.0080.00018.05
8.2.50.0040.00418.09
8.2.40.0000.00822.31
8.2.30.0040.00419.62
8.2.20.0040.00417.79
8.2.10.0030.00518.23
8.2.00.0060.00618.16
8.1.330.0120.00822.13
8.1.320.0080.01116.14
8.1.310.0070.01016.83
8.1.300.0040.01220.31
8.1.290.0030.00630.84
8.1.280.0130.00725.92
8.1.270.0080.00023.84
8.1.260.0090.00028.09
8.1.250.0040.00428.09
8.1.240.0030.00722.54
8.1.230.0070.00319.10
8.1.220.0050.00517.78
8.1.210.0000.00818.77
8.1.200.0060.00317.25
8.1.190.0080.00017.23
8.1.180.0040.00418.10
8.1.170.0000.00818.71
8.1.160.0000.00720.81
8.1.150.0040.00419.07
8.1.140.0040.00419.59
8.1.130.0080.00017.69
8.1.120.0000.00717.56
8.1.110.0000.00717.39
8.1.100.0040.00417.40
8.1.90.0000.00817.54
8.1.80.0000.00817.52
8.1.70.0040.00417.36
8.1.60.0030.00517.65
8.1.50.0030.00617.50
8.1.40.0080.00017.55
8.1.30.0040.00417.73
8.1.20.0080.00017.70
8.1.10.0060.00317.65
8.1.00.0080.00017.45
8.0.300.0000.00718.77
8.0.290.0000.00716.63
8.0.280.0000.00718.41
8.0.270.0030.00317.38
8.0.260.0030.00317.23
8.0.250.0030.00316.95
8.0.240.0040.00416.95
8.0.230.0070.00016.98
8.0.220.0040.00416.86
8.0.210.0030.00316.81
8.0.200.0050.00217.02
8.0.190.0030.00517.00
8.0.180.0070.00016.97
8.0.170.0080.00017.02
8.0.160.0080.00017.04
8.0.150.0000.00816.89
8.0.140.0040.00416.76
8.0.130.0000.00513.41
8.0.120.0040.00416.92
8.0.110.0040.00416.86
8.0.100.0000.00816.93
8.0.90.0040.00416.89
8.0.80.0130.00916.99
8.0.70.0070.00016.98
8.0.60.0080.00016.82
8.0.50.0000.00716.81
8.0.30.0090.00817.07
8.0.20.0180.00317.43
8.0.10.0050.00317.02
8.0.00.0120.00716.76
7.4.330.0050.00015.11
7.4.320.0040.00416.55
7.4.300.0100.00016.66
7.4.290.0030.00316.65
7.4.280.0090.00316.46
7.4.270.0070.00016.55
7.4.260.0000.00716.68
7.4.250.0000.00716.52
7.4.240.0070.00016.51
7.4.230.0080.00016.76
7.4.220.0060.01116.72
7.4.210.0080.01116.59
7.4.200.0070.00016.65
7.4.160.0090.00616.74
7.4.150.0210.01017.40
7.4.140.0110.00617.86
7.4.130.0080.01016.47
7.4.120.0140.00616.66
7.4.110.0070.01016.50
7.4.100.0140.01016.57
7.4.90.0070.01016.55
7.4.80.0150.00619.39
7.4.70.0070.01016.35
7.4.60.0060.01016.63
7.4.50.0030.01016.43
7.4.40.0060.01216.36
7.4.30.0110.00516.60
7.4.00.0070.01015.07
7.3.330.0050.00013.39
7.3.320.0000.00513.27
7.3.310.0040.00416.50
7.3.300.0000.00716.27
7.3.290.0000.00716.40
7.3.280.0100.00716.42
7.3.270.0170.00417.40
7.3.260.0090.00916.62
7.3.250.0100.01116.54
7.3.240.0130.00616.59
7.3.230.0190.00316.39
7.3.210.0130.00316.61
7.3.200.0100.00719.39
7.3.190.0140.00316.38
7.3.180.0110.01116.50
7.3.170.0060.01216.54
7.3.160.0040.01216.70
7.3.120.0000.01515.15
7.3.110.0090.00614.80
7.3.100.0000.01414.81
7.3.90.0000.01614.88
7.3.80.0060.00914.54
7.3.70.0000.01214.78
7.3.60.0130.00014.63
7.3.50.0140.00014.80
7.3.40.0070.00714.68
7.3.30.0140.00014.97
7.3.20.0040.01116.72
7.3.10.0090.00416.59
7.3.00.0080.00816.68
7.2.330.0030.01916.71
7.2.320.0080.00816.68
7.2.310.0040.01416.77
7.2.300.0140.00316.76
7.2.290.0060.01616.51
7.2.240.0080.00315.24
7.2.230.0110.00414.87
7.2.220.0070.00715.25
7.2.210.0060.00614.98
7.2.200.0070.00715.32
7.2.190.0080.00415.03
7.2.180.0060.00315.26
7.2.170.0060.00915.20
7.2.160.0050.00515.16
7.2.150.0070.01017.12
7.2.140.0070.00716.78
7.2.130.0020.01517.04
7.2.120.0100.00516.86
7.2.110.0070.01116.84
7.2.100.0100.00616.91
7.2.90.0080.00816.97
7.2.80.0090.00616.90
7.2.70.0080.00716.76
7.2.60.0070.00717.06
7.2.50.0090.00416.64
7.2.40.0030.01016.89
7.2.30.0080.00516.97
7.2.20.0020.01216.81
7.2.10.0070.00616.79
7.2.00.0030.00717.75
7.1.330.0060.00615.60
7.1.320.0040.01215.77
7.1.310.0120.00315.89
7.1.300.0030.01215.74
7.1.290.0000.01415.88
7.1.280.0000.00815.75
7.1.270.0000.01215.98
7.1.260.0070.01015.88
7.1.250.0090.00715.82
7.1.200.0090.00315.86
7.1.100.0160.00317.99
7.1.70.0000.00817.38
7.1.60.0060.01919.85
7.1.00.0070.07322.42
7.0.200.0120.00314.98
7.0.60.0100.05720.12
7.0.50.0200.05320.25
7.0.40.0270.04720.26
7.0.30.0130.05720.26
7.0.20.0230.05320.35
7.0.10.0130.06320.47
7.0.00.0200.06020.45
5.6.280.0000.07721.15
5.6.210.0100.06020.73
5.6.200.0100.06321.05
5.6.190.0200.06321.10
5.6.180.0230.04721.18
5.6.170.0200.05021.08
5.6.160.0200.05721.05
5.6.150.0230.06021.14
5.6.140.0170.05321.19
5.6.130.0470.06021.08
5.6.120.0170.06321.14
5.6.110.0230.05721.09
5.6.100.0200.05021.07
5.6.90.0070.06720.96
5.6.80.0230.04720.52
5.6.70.0100.06020.43
5.6.60.0200.04720.40
5.6.50.0130.06720.61
5.6.40.0070.05720.50
5.6.30.0300.05720.58
5.6.20.0370.05320.49
5.6.10.0330.05720.43
5.6.00.0400.05020.53
5.5.350.0300.04320.60
5.5.340.0170.05720.76
5.5.330.0170.05720.89
5.5.320.0200.04720.79
5.5.310.0170.06720.77
5.5.300.0070.06720.89
5.5.290.0170.05720.90
5.5.280.0200.05320.91
5.5.270.0170.05321.04
5.5.260.0230.04320.87
5.5.250.0270.06320.86
5.5.240.0170.05320.28
5.5.230.0200.05720.27
5.5.220.0200.05020.42
5.5.210.0170.05320.42
5.5.200.0070.05720.32
5.5.190.0530.05020.24
5.5.180.0470.04720.16
5.5.160.0330.06720.22
5.5.150.0470.05320.23
5.5.140.0400.06020.23
5.5.130.0430.05720.20
5.5.120.0400.06020.22
5.5.110.0430.05320.41
5.5.100.0370.05720.14
5.5.90.0430.05020.10
5.5.80.0400.05720.07
5.5.70.0370.05720.28
5.5.60.0530.03720.20
5.5.50.0370.05320.14
5.5.40.0430.04720.07
5.5.30.0300.06020.15
5.5.20.0430.05720.08
5.5.10.0370.06020.09
5.5.00.0430.05320.05

preferences:
31.55 ms | 403 KiB | 5 Q