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run code in 300+ PHP versions simultaneously
<?php function wrap( $arr){ test( $arr); } function test( $arr){ $refs = array(); // Array of references that we've seen $f = function( $arr) use( &$refs, &$f) { $refs[] = $arr; foreach( $arr as $v) { if( in_array( $v, $refs, true)) { print 'ref, '; } else { if( is_array( $v)) { $f( $v); } else { print $v . ', '; } } } }; $f( $arr); } $array = array(1, 2, array(1, 2), array(1, 2)); wrap( $array);

preferences:
60.04 ms | 402 KiB | 5 Q