Table of Contents
What is a non-greedy regex?
A non-greedy match means that the regex engine matches as few characters as possible—so that it still can match the pattern in the given string. For example, the regex ‘a+?’ will match as few ‘a’ s as possible in your string ‘aaaa’ . Thus, it matches the first character ‘a’ and is done with it.
How do you make a lazy regex?
‘Lazy’ means match shortest possible string. For example, the greedy h. +l matches ‘hell’ in ‘hello’ but the lazy h….12 Answers.
| Greedy quantifier | Lazy quantifier | Description |
|---|---|---|
| {n} | {n}? | Quantifier: exactly n |
| {n,} | {n,}? | Quantifier: n or more |
| {n,m} | {n,m}? | Quantifier: between n and m |
What is greedy regex?
Greedy: As Many As Possible (longest match) By default, a quantifier tells the engine to match as many instances of its quantified token or subpattern as possible. This behavior is called greedy.
How do I make something optional in regex?
Optional Items
- The question mark makes the preceding token in the regular expression optional.
- You can make several tokens optional by grouping them together using parentheses, and placing the question mark after the closing parenthesis.
What makes a search non-greedy?
To make the quantifier non-greedy you simply follow it with a ‘?’ the first 3 characters and then the following ‘ab’ is matched. greedy by appending a ‘?’ symbol to them: *?, +?,??, {n,m}?, and {n,}?.
What is a word for not greedy?
altruistic, apathetic, benevolent, full, generous, indifferent, munificent, self-restrained, unselfish.
Is regex greedy by default?
Regular expressions aren’t greedy by default, but their quantifiers are 🙂 It seems to me the real question is, why are lazy quantifiers more poorly supported and/or awkward to use than greedy ones?
What are quantifiers regex?
Quantifiers specify how many instances of a character, group, or character class must be present in the input for a match to be found.
What is optional character in regex?
This metacharacter allows you to match either zero or one of the preceding character or group. For example, the pattern ab? c will match either the strings “abc” or “ac” because the b is considered optional.
How do I make a group optional in regex python?
So to make any group optional, we need to have to put a “?” after the pattern or group. This question mark makes the preceding group or pattern optional. This question mark is also known as a quantifier.
Is a regex character?
A regex consists of a sequence of characters, metacharacters (such as . , \d , \D , \ s, \S , \w , \W ) and operators (such as + , * ,? , | , ^ ). They are constructed by combining many smaller sub-expressions.
What’s the opposite of not greedy?
The opposite of being greedy is being generous—being willing to give away one’s money or possessions instead of being obsessed with acquiring more.
