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run code in 300+ PHP versions simultaneously
<?php $x = new ArrayIterator( array( 'foo' => 1, 'bar' => 2, ) ); $keys = array_keys( $x ); if ( ! empty( $keys ) && is_array( $keys ) ) { print "PASS"; } else { print "FAIL"; }

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63.87 ms | 402 KiB | 5 Q