<?php
 
// com opção 'u' (Unicode), \w retorna 1 (match)
// acentos (è e á)
print(preg_match('/^\w+$/u', 'lumière'). "\n");
print(preg_match('/^\w+$/u', 'á'). "\n");
// caracteres japoneses
print(preg_match('/^\w+$/u', '今日'). "\n");
 
// não usar \w, todos retornam 0 (não dá match), mesmo usando opção 'u'
print(preg_match('/^[A-Za-z0-9_]+$/u', 'lumière'). "\n");
print(preg_match('/^[A-Za-z0-9_]+$/u', 'á'). "\n");
print(preg_match('/^[A-Za-z0-9_]+$/u', '今日'). "\n");
 
 
 

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