正则表达式使用案例-OCP试题

92. Evaluate the following expression using Meta. character for regular expression:
'[^Ale|ax.r$]'
Which two matches would be returned by this expression? (Choose two.)
A. Alex
B. Alax
C. Alxer
D. Alaxendar
E. Alexender
Answer: DE

解析：题目的意思是哪两个选项能和'[^Ale|ax.r$]'匹配
'[^Ale|ax.r$]'中^表示只匹配不在集合{'A','l','e','|','a','x','.','r','$'}中的字符,此处的'|'、'.'、'$'只是表示普通的字符，而非匹配符 select regexp_instr('Alex','[^Ale|ax.r$]') from dual; REGEXP_INSTR('ALEX','[^ALE|AX.R$]') ----------------------------------- 0 select regexp_instr('Alax','[^Ale|ax.r$]') from dual; REGEXP_INSTR('ALAX','[^ALE|AX.R$]') ----------------------------------- 0 select regexp_instr('Alxer','[^Ale|ax.r$]') from dual; REGEXP_INSTR('ALXER','[^ALE|AX.R$]') ------------------------------------ 0 select regexp_instr('Alaxendar','[^Ale|ax.r$]') from dual; REGEXP_INSTR('ALAXENDAR','[^ALE|AX.R$]') ---------------------------------------- 6 select regexp_instr('Alexender','[^Ale|ax.r$]') from dual; REGEXP_INSTR('ALEXENDER','[^ALE|AX.R$]') ---------------------------------------- 6 因此可见答案是DE 转自：http://www.itpub.net/forum.PHP?mod=viewthread&tid=1327778