Podcast
Questions and Answers
What is the purpose of the \b anchor in regular expressions?
What is the purpose of the \b anchor in regular expressions?
- To match a word boundary (correct)
- To match a whitespace character
- To match a digit
- To match the start of a string
What is the difference between a capturing group and a non-capturing group in regular expressions?
What is the difference between a capturing group and a non-capturing group in regular expressions?
- A capturing group matches more characters than a non-capturing group
- A capturing group is used for quantifiers, while a non-capturing group is used for anchors
- A capturing group is used for positive lookahead, while a non-capturing group is used for negative lookahead
- A capturing group remembers the match, while a non-capturing group does not (correct)
What is the purpose of the (?:abc) syntax in regular expressions?
What is the purpose of the (?:abc) syntax in regular expressions?
- To create a non-capturing group (correct)
- To match the string 'abc' exactly
- To create a capturing group
- To match the string 'abc' in a case-insensitive manner
What does the quantifier a{1,3} match in regular expressions?
What does the quantifier a{1,3} match in regular expressions?
What is the purpose of the \W character class in regular expressions?
What is the purpose of the \W character class in regular expressions?
What does the character class [a-g] match in regular expressions?
What does the character class [a-g] match in regular expressions?
What is the purpose of the character in regular expressions?
What is the purpose of the character in regular expressions?
What does the regular expression a{2,} match?
What does the regular expression a{2,} match?
What is the purpose of the (?=abc) syntax in regular expressions?
What is the purpose of the (?=abc) syntax in regular expressions?
What does the regular expression a+?a{2,}? match?
What does the regular expression a+?a{2,}? match?
Study Notes
Character Classes
- Any character except newline:
\w,\d,\smatch word, digit, whitespace respectively - Not word, digit, whitespace:
\W,\D,\Srespectively - Match any of a, b, or c:
[abc] - Not a, b, or c:
[^abc] - Character between a & g:
[a-g]
Anchors
- Start of the string:
^ - End of the string:
$ - Word boundary:
\b - Not-word boundary:
\B
Escaped Characters
- Escaped special characters:
\.,\\ - Tab, linefeed, carriage return:
\t,\n,\r
Groups & Lookaround
- Capture group:
(abc) - Backreference to group #1:
\1 - Non-capturing group:
(?:abc) - Positive lookahead:
(?=abc) - Negative lookahead:
(?!abc)
Quantifiers & Alternation
- 0 or more, 1 or more, 0 or 1:
a*,a+,a? - Exactly five, two or more:
a{5},a{2,} - Between one & three:
a{1,3} - Match as few as possible:
a+?,a{2,}? - Match ab or cd:
ab|cd
Character Classes
- Any character except newline:
\w,\d,\smatch word, digit, whitespace respectively - Not word, digit, whitespace:
\W,\D,\Srespectively - Match any of a, b, or c:
[abc] - Not a, b, or c:
[^abc] - Character between a & g:
[a-g]
Anchors
- Start of the string:
^ - End of the string:
$ - Word boundary:
\b - Not-word boundary:
\B
Escaped Characters
- Escaped special characters:
\.,\\ - Tab, linefeed, carriage return:
\t,\n,\r
Groups & Lookaround
- Capture group:
(abc) - Backreference to group #1:
\1 - Non-capturing group:
(?:abc) - Positive lookahead:
(?=abc) - Negative lookahead:
(?!abc)
Quantifiers & Alternation
- 0 or more, 1 or more, 0 or 1:
a*,a+,a? - Exactly five, two or more:
a{5},a{2,} - Between one & three:
a{1,3} - Match as few as possible:
a+?,a{2,}? - Match ab or cd:
ab|cd
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Description
Test your understanding of character classes, anchors, and groups in regular expressions. Learn to match patterns and create efficient regex expressions.
