5位或无数字字符串的正则表达式

Question

Am trying to write a regex that captures a string followed by exactly 5 or no digits

Regex should match Passport Passport11111 Passport12345 but shouldn't match Passport1 Passport123 Passport123456

I tried using Passport\\d{5*} but its not working. Can someone please help me?

Answer 1

You almost had it.

Passport(\d{5})?

The parentheses capture their contents (ie they create a group), but they also provide a way to make a part of the pattern atomic, so you can - for example - make it optional with ? .

BTW, you can write parentheses that don't capture but make atomic only by adding an option to them:

Passport(?:\d{5})?