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regex.search

The regex.search function reports whether a regular expression matches anywhere in a string. Use it to branch on the shape of a value, such as a version number, a stack name, or a line of command output.

Usage​

regex.search(pattern, text)

Arguments​

pattern

Required. The regular expression, as a string. Atmos uses RE2 syntax: character classes, groups, alternation, repetition, and anchors work, and inline flags such as (?i) for case-insensitive matching and (?m) for multi-line anchors are supported. Lookahead, lookbehind, and backreferences in the pattern are not available. In a Python-style string, write a backslash as \\, as in "\\d+", or use a raw string such as r"\d+".

text
Required. The string to search.

Both arguments are required and can be passed positionally or by keyword.

Returns​

A boolean: True when the pattern matches anywhere in text, and False otherwise. The result is a boolean, not a match object. Use regex.findall to retrieve the matched text.

Examples​

Check a version format​

tag = "v1.2.3"
output = "release" if regex.search("^v[0-9]+\\.[0-9]+", tag) else "snapshot"
release

Match without regard to case​

print(regex.search("(?i)prod", "Env: PROD"))
True

Anchor to each line​

Without (?m), ^ matches only at the start of the whole string:

print(regex.search("^dev", "x\ndev"))
print(regex.search("(?m)^dev", "x\ndev"))
False
True

Filter stacks in a loop​

stacks = ["plat-use1-dev", "plat-use1-prod", "plat-usw2-dev"]
prod = [s for s in stacks if regex.search("-prod$", s)]
output = prod
["plat-use1-prod"]

Use keyword arguments​

print(regex.search(text = "abc", pattern = "b"))
True

Errors​

  • A pattern that is not valid RE2 fails with invalid regex: ... followed by the reason, for example invalid regex: error parsing regexp: missing closing ): (. Lookahead such as (?=a) and backreferences such as \1 fail the same way.
  • A missing argument, or an argument that is not a string, fails with an argument error.

Related​