re.md

re

Regular expressions using Go's regexp package.

use "re"

All functions take the pattern as the first argument. Invalid patterns panic (use try/or to handle).

Functions

re.test(pattern, s)

Returns true if the pattern matches anywhere in the string.

re.test("^\\d+$", "42")      # true
re.test("^\\d+$", "abc")     # false

re.find(pattern, s)

Returns the first match, or nil if no match.

re.find("\\d+", "abc123def")   # "123"
re.find("\\d+", "no numbers")  # nil

re.find_all(pattern, s)

Returns all matches as an array.

re.find_all("\\d+", "a1b2c3")  # ["1", "2", "3"]

re.replace(pattern, s, replacement)

Replaces the first match.

re.replace("\\d+", "a1b2c3", "X")  # "aXb2c3"

re.replace_all(pattern, s, replacement)

Replaces all matches. Supports backreferences ($1, $2).

re.replace_all("\\d+", "a1b2c3", "X")                     # "aXbXcX"
re.replace_all("(\\w+)@(\\w+)", "foo@bar", "$1 at $2")     # "foo at bar"

re.split(pattern, s)

Splits the string by the pattern. Returns an array.

re.split("\\s+", "hello   world")   # ["hello", "world"]
re.split(",\\s*", "a, b, c")        # ["a", "b", "c"]

re.match(pattern, s)

Returns a hash with "match" (full match string) and "groups" (array of capture groups), or nil if no match.

m = re.match("(\\w+)@(\\w+)", "foo@bar.com")
m["match"]      # "foo@bar"
m["groups"][0]   # "foo"
m["groups"][1]   # "bar"

Error Handling

Invalid patterns panic with a descriptive message. Use try/or to handle:

result = try re.test("[invalid", "test") or "bad pattern"