在PHP中检查数组是否递归的最佳方法是什么？给定以下代码:来自PHPManual:Theprint_r()willdisplayRECURSIONwhenitgetstothethirdelementofthearray.Theredoesn'tappeartobeanyotherwaytoscananarrayforrecursivereferences,soifyouneedtocheckforthem,you'llhavetouseprint_r()withitssecondparametertocapturetheoutputandlookforthewordRECURSION