3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = array(0, 1, 2); foreach ($arr as &$v) { $v += 1; } foreach ($arr as $v) { var_dump($v); } /* Output: int(1) int(2) int(2) Lines 2-4 iterate over $arr by reference. So, when we reach line 5, $v is still a reference to last element of the array (e.g. $v = &$arr[2]). There are only 2 possible ways to "unlink" $v from the array element: - use unset(): unset($v); - make $v a reference to another value: $v = &$x; Since $v is reference to last element of the array, the foreach loop in lines 5-7 will execute like this: 1) $v = $arr[0]; $arr is now [1, 2, 1], since writing to $v updates $arr[2] 2) $v = $arr[1]; $arr is now [1, 2, 2], since writing to $v updates $arr[2] 3) $v = $arr[2]; This causes self-assignment (e.g. $arr[2] = $arr[2]), which doesn't change the value of $arr. */

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)
8.4.20.0080.00820.95
8.4.10.0030.00617.52
8.3.140.0120.00616.68
8.3.130.0030.00616.64
8.3.120.0100.00620.95
8.3.110.0060.01218.46
8.3.100.0080.00024.06
8.3.90.0040.00426.77
8.3.80.0030.00618.43
8.3.70.0110.00718.68
8.3.60.0150.00618.56
8.3.50.0090.00418.40
8.3.40.0110.00418.75
8.3.30.0170.00318.34
8.3.20.0000.00720.53
8.3.10.0110.00322.02
8.3.00.0090.00922.48
8.2.260.0150.00418.30
8.2.250.0030.00616.56
8.2.240.0000.00817.09
8.2.230.0040.00420.94
8.2.220.0000.00937.54
8.2.210.0080.00026.77
8.2.200.0050.00518.29
8.2.190.0120.00316.58
8.2.180.0090.00618.13
8.2.170.0090.00619.08
8.2.160.0070.00722.96
8.2.150.0070.00025.66
8.2.140.0080.00024.66
8.2.130.0040.00426.16
8.2.120.0040.00421.18
8.2.110.0000.00920.35
8.2.100.0040.00718.03
8.2.90.0080.00017.84
8.2.80.0040.00417.97
8.2.70.0000.00817.63
8.2.60.0090.00018.22
8.2.50.0000.00818.10
8.2.40.0040.00419.51
8.2.30.0000.00818.21
8.2.20.0030.00618.16
8.2.10.0040.00419.55
8.2.00.0040.00419.37
8.1.310.0080.00818.48
8.1.300.0130.00718.50
8.1.290.0030.00718.88
8.1.280.0110.00425.92
8.1.270.0040.00424.66
8.1.260.0040.01126.35
8.1.250.0040.00428.09
8.1.240.0030.00622.46
8.1.230.0060.00622.66
8.1.220.0050.00317.79
8.1.210.0040.00418.77
8.1.200.0030.00617.36
8.1.190.0000.00817.23
8.1.180.0080.00018.10
8.1.170.0050.00318.25
8.1.160.0000.00818.89
8.1.150.0000.00718.87
8.1.140.0040.00421.97
8.1.130.0030.00317.36
8.1.120.0050.00417.36
8.1.110.0040.00417.49
8.1.100.0030.00617.45
8.1.90.0060.00317.46
8.1.80.0050.00317.53
8.1.70.0080.00317.44
8.1.60.0000.00917.43
8.1.50.0030.00517.54
8.1.40.0060.00317.56
8.1.30.0090.00517.57
8.1.20.0120.00417.66
8.1.10.0120.00417.40
8.1.00.0140.00317.34
8.0.300.0040.00420.03
8.0.290.0000.00916.63
8.0.280.0040.00418.44
8.0.270.0040.00416.81
8.0.260.0080.00016.77
8.0.250.0070.00016.93
8.0.240.0050.00516.96
8.0.230.0000.00716.84
8.0.220.0040.00416.88
8.0.210.0070.00016.95
8.0.200.0030.00317.04
8.0.190.0040.00416.91
8.0.180.0060.00316.91
8.0.170.0090.00016.85
8.0.160.0080.00616.90
8.0.150.0120.00116.73
8.0.140.0100.00516.73
8.0.130.0080.00515.07
8.0.120.0080.00516.84
8.0.110.0110.00216.76
8.0.100.0120.00216.83
8.0.90.0070.00716.85
8.0.80.0130.00716.86
8.0.70.0060.00816.75
8.0.60.0080.00616.84
8.0.50.0080.00516.69
8.0.30.0130.00717.02
8.0.20.0110.00816.93
8.0.10.0070.00716.97
8.0.00.0110.00916.79
7.4.330.0020.00215.55
7.4.320.0000.00716.60
7.4.300.0030.00316.47
7.4.290.0070.00016.42
7.4.280.0030.00516.49
7.4.270.0060.00416.57
7.4.260.0070.00514.89
7.4.250.0100.00416.42
7.4.240.0060.00716.49
7.4.230.0120.00216.52
7.4.220.0050.00516.53
7.4.210.0100.00516.53
7.4.200.0080.00316.53
7.4.190.0140.00316.57
7.4.180.0130.00616.61
7.4.160.0110.00316.54
7.4.150.0140.00316.61
7.4.140.0160.00016.34
7.4.130.0100.01116.37
7.4.120.0060.00916.27
7.4.110.0100.00516.42
7.4.100.0040.01216.29
7.4.90.0080.00816.43
7.4.80.0120.00617.27
7.4.70.0090.00716.40
7.4.60.0090.00816.39
7.4.50.0080.00616.33
7.4.40.0100.00816.32
7.4.30.0150.00416.32
7.4.20.0120.00516.40
7.4.10.0090.00716.38
7.4.00.0080.00815.95
7.3.330.0110.00216.12
7.3.320.0100.00314.68
7.3.310.0110.00416.13
7.3.300.0120.00216.24
7.3.290.0080.00416.19
7.3.280.0090.01116.20
7.3.270.0180.00016.20
7.3.260.0120.00916.38
7.3.250.0150.00516.31
7.3.240.0080.00916.29
7.3.230.0140.00516.33
7.3.220.0120.00716.23
7.3.210.0110.00716.38
7.3.200.0120.00516.26
7.3.190.0120.00616.23
7.3.180.0100.00916.36
7.3.170.0110.00716.37
7.3.160.0110.00816.32
7.3.150.0100.00716.41
7.3.140.0090.00816.27
7.3.130.0100.00716.31
7.3.120.0100.00716.03
7.3.110.0080.00915.93
7.3.100.0090.00715.65
7.3.90.0080.00815.63
7.3.80.0090.00815.64
7.3.70.0100.00715.60
7.3.60.0080.00815.59
7.3.50.0080.00915.61
7.3.40.0110.00515.55
7.3.30.0090.00715.60
7.3.20.0130.00716.46
7.3.10.0100.00716.36
7.3.00.0110.00616.37
7.2.340.0170.00316.40
7.2.330.0120.00816.43
7.2.320.0110.00716.48
7.2.310.0130.00616.42
7.2.300.0120.00716.46
7.2.290.0120.00816.35
7.2.280.0090.01016.41
7.2.270.0100.00916.39
7.2.260.0110.00816.47
7.2.250.0100.00816.18
7.2.240.0090.01116.11
7.2.230.0090.00815.75
7.2.220.0090.00715.83
7.2.210.0100.00715.83
7.2.200.0080.00915.76
7.2.190.0090.00915.73
7.2.180.0080.00915.84
7.2.170.0090.00915.80
7.2.160.0090.00715.77
7.2.150.0100.00816.63
7.2.140.0110.00616.64
7.2.130.0090.00816.71
7.2.120.0100.00816.55
7.2.110.0110.00816.62
7.2.100.0100.00816.61
7.2.90.0100.00916.69
7.2.80.0100.00816.49
7.2.70.0110.00916.58
7.2.60.0120.00916.59
7.2.50.0100.01016.61
7.2.40.0100.00816.74
7.2.30.0140.00516.73
7.2.20.0080.01016.59
7.2.10.0090.00916.69
7.2.00.0130.00416.61
7.1.330.0190.00615.95
7.1.320.0130.00715.60
7.1.310.0110.00715.65
7.1.300.0160.00715.63
7.1.290.0130.00815.54
7.1.280.0100.00915.64
7.1.270.0080.01115.54
7.1.260.0130.00715.56
7.1.250.0110.00815.49
7.1.240.0110.00915.91
7.1.230.0130.00815.88
7.1.220.0120.00915.77
7.1.210.0140.00615.85
7.1.200.0140.00715.89
7.1.190.0130.00615.82
7.1.180.0120.00815.86
7.1.170.0150.00415.96
7.1.160.0170.00715.76
7.1.150.0130.00715.78
7.1.140.0130.00815.86
7.1.130.0110.00715.86
7.1.120.0110.00815.87
7.1.110.0110.00915.85
7.1.100.0160.00715.89
7.1.90.0110.00815.97
7.1.80.0110.00815.90
7.1.70.0110.00815.76
7.1.60.0110.00915.87
7.1.50.0130.00715.93
7.1.40.0120.00715.86
7.1.30.0150.00515.86
7.1.20.0110.01115.94
7.1.10.0120.00915.82
7.1.00.0140.00815.84

preferences:
73.94 ms | 403 KiB | 5 Q