Finds zero or one of the characters in front of the &quot; ? &quot; . For example, &quot; Texts? &quot; finds &quot; Text &quot; and &quot; Texts &quot; and &quot; x(ab_BAR_c)?y &quot; finds &quot; xy &quot; , &quot; xaby &quot; , or &quot; xcy &quot; .
查找 &quot; ? &quot; 前的一个字符出现N（N=0 或 N=1）次的情况。例如， &quot; Texts? &quot; 将查找 &quot; Text &quot; 和 &quot; Texts &quot; ，而 &quot; (ab_BAR_c)?y &quot; 将查找 &quot; xy &quot; 、 &quot; xaby &quot; 或 &quot; xcy &quot; 。