Quantifiers specify how many instances of the previous element (which can be a character, a group, or a character class) must be present in the input string for a match to occur.
| Quantifier | Description | Pattern | Matches |
|---|---|---|---|
| * | Matches the previous element zero or more times. | \d*\.\d | ".0", "19.9", "219.9" |
| + | Matches the previous element one or more times. | "be+" | "bee" in "been", "be" in "bent" |
| ? | Matches the previous element zero or one time. | "rai?n" | "ran", "rain" |
| { n } | Matches the previous element exactly n times. | ",\d{3}" | ",043" in "1,043.6", ",876", ",543", and ",210" in "9,876,543,210" |
| { n ,} | Matches the previous element at least n times. | "\d{2,}" | "166", "29", "1930" |
| { n , m } | Matches the previous element at least n times, but no more than m times. | "\d{3,5}" | "166", "17668" "19302" in "193024" |
| *? | Matches the previous element zero or more times, but as few times as possible. | \d*?\.\d | ".0", "19.9", "219.9" |
| +? | Matches the previous element one or more times, but as few times as possible. | "be+?" | "be" in "been", "be" in "bent" |
| ?? | Matches the previous element zero or one time, but as few times as possible. | "rai??n" | "ran", "rain" |
| { n }? | Matches the preceding element exactly n times. | ",\d{3}?" | ",043" in "1,043.6", ",876", ",543", and ",210" in "9,876,543,210" |
| { n ,}? | Matches the previous element at least n times, but as few times as possible. | "\d{2,}?" | "166", "29", "1930" |
| { n , m }? | Matches the previous element between n and m times, but as few times as possible. | "\d{3,5}?" | "166", "17668" "193", "024" in "193024" |
No comments:
Post a Comment