(PHP 5, PHP 7, PHP 8)
RecursiveIteratorIterator::valid โ ็พๅจใฎไฝ็ฝฎใๆๅนใใฉใใใใใงใใฏใใ
ใใฎ้ขๆฐใฏใ ็พๅจใฎใจใใ่ฉณ็ดฐใชๆ ๅ ฑใฏใใใพใใใๅผๆฐใฎใชในใใฎใฟใ ่จ่ฟฐใใใฆใใพใใ
ใใฎ้ขๆฐใซใฏใใฉใกใผใฟใฏใใใพใใใ