The meaning of the regular expression ¥d.+?yen

The \\ attached to your question is also a circle symbol, so please use \\ when you are actually trying.(If you copy, it may look garbled, but don't panic and choose the correct one.)

Now, if you look at String regex="\\d.+?yen", removing the escape as a Java string means passing the \d.<

If you look at it in order,

• \d—Matches a digit in regular expression, one decimal character.
• .—The most commonly used meta-character in regular expressions, but matches any character other than a new line (*).
• +?—Indicates that the quantified meta-character repeats the previous element 最短one or more minimum matches.
• yen—Indicates that each matches the character itself.

When applied to the str you suggested, the first find() is as follows:
- \d:1
- .+?:00
- yen:yen

Therefore, if you add a code that displays the entire match, you should know that 100yen is a match.

By the way, removing ? after + in the pattern will be the longest match, so 100yen, Lemon is 80yen will match on the first find().

Roughly speaking, the original regular expression pattern is a pattern that looks for "starting with a number and ending with the most recent yen.

There is also an option to instruct (*). to match line breaks as well.