Regex Pattern Matching Quiz

* matches 0 or more of the preceding item:

/hel*o/ matches "heo", "helo", "hello", "helllo"

+ matches 1 or more of the preceding item:

/hel+o/ matches "helo", "hello", "helllo" but not "heo"

? matches 0 or 1 of the preceding item:

/hel?o/ matches "heo" and "helo" but not "hello"

{n} matches exactly n occurrences:

/hel{2}o/ matches "hello" but not "helo"

^ matches the start of a string:

/^hello/ matches "hello world" but not "world hello"

$ matches the end of a string:

/world$/ matches "hello world" but not "world hello"

\b matches a word boundary:

/\bhello\b/ matches "hello" but not "helloworld"

\d matches any digit (0-9):

/\d+/ matches "123"

\w matches any word character (a-z, A-Z, 0-9, _):

/\w+/ matches "hello_123"

\s matches any whitespace character:

/hello\sworld/ matches "hello world"

Negated character classes match anything not in the class:

/[^0-9]/ matches any non-digit character

Parentheses create capturing groups:

/(\d{3})-(\d{3})/ matches "123-456" capturing "123" and "456"

The pipe | means OR:

/cat|dog/ matches "cat" or "dog"

Non-capturing groups use (?:...):

/(?:https?|ftp):\/\// matches "http://" or "https://" or "ftp://" without capturing

Pattern alternation works similarly to logical conditions in JavaScript conditionals—both evaluate multiple possibilities.

i - Case insensitive matching:

/hello/i matches "Hello", "HELLO", "hElLo"

g - Global matching (find all matches):

/a/g finds all "a" characters in a string

m - Multiline mode (^ and $ match start/end of lines):

/^hello/gm matches "hello" at the start of each line

s - Dot matches newline characters:

/hello.world/s matches "hello\nworld"