Online PHP editor | refs for hABgk

<?php $strings = [ 'stage', // expect empty string '8.-10. stage', // expect 8 '8. stage', // expect 8 '8.-10. stage 1st', // expect 8 'Test 8. stage 2020', // expect 8 'Test 8.-10. stage - 2020 test', // expect 8 'A1B2C3D4D5E6F7G8', // expect 1 '1000', // expect 1000 'Test 2020', // ecpect 2020 ]; var_export( preg_replace('/^\D+|\d+\K.*/', '', $strings) );