Regex literals, character classes, quantifiers, anchors, groups, alternation and common flags.
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- What does a regex literal represent?
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A sequence of characters that defines a pattern to search for or match in text.- What does the dot (.) metacharacter match in regex?
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Any single character except a newline (in standard mode).- How do you match a literal period in regex?
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Escape it with a backslash: \.- What does the pipe | operator do in regex?
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It creates alternation, matching any one of the patterns separated by |.- What is a character class in regex?
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A set of characters enclosed in square brackets [] that matches any single character in the set.- What does \d match in regex?
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Any digit, 0 through 9.- What does \w match in regex?
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Any word character: a-z, A-Z, 0-9, and underscore (_).- What does \s match in regex?
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Any whitespace character: space, tab, newline, carriage return, or form feed.- What does [a-z] represent in regex?
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Any single lowercase letter from a to z.- What does [^abc] represent in regex?
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Any single character except a, b, or c (negation of the character class).- What does the + quantifier mean?
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Match one or more of the preceding element.- What does {n} mean as a quantifier?
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Match exactly n occurrences of the preceding element.- What does {n,m} mean as a quantifier?
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Match between n and m occurrences of the preceding element (inclusive).- How do you make a quantifier non-greedy?
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Add a ? after the quantifier (e.g., +?, *?, ??, {n,m}?).- What is the difference between greedy and non-greedy matching?
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Greedy matches as much as possible; non-greedy matches as little as possible.
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