optionalPattern - Make pattern optional to match - MATLAB (original) (raw)

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Make pattern optional to match

Since R2020b

Syntax

Description

[newpat](#mw%5Fd8c30aba-5090-45f1-a5ae-f65f8863c423%5Fsep%5Fmw%5F2527cdca-90c8-43b1-8ea8-8fa52700322c) = optionalPattern([pat](#mw%5Fd8c30aba-5090-45f1-a5ae-f65f8863c423%5Fsep%5Fmw%5F619a0af2-3091-404f-9c61-e268bcf7fbcb)) creates a pattern that matches pat when possible, but matchingpat is not required for a pattern expression to match successfully. Use this function in conjunction with other pattern functions to build patterns that are more flexible in their matching requirements.

example

Examples

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Use optionalPattern to designate a pattern as optional to match.

Create txt as a string. Create a pattern, pat, that matches "foo" and will optionally match "bar" so long as it is preceded by "foo". Extract the pattern.

txt = "foo bar foobar"; pat = "foo" + optionalPattern("bar"); extract(txt,pat)

ans = 2×1 string "foo" "foobar"

Build a pattern that matches combinations of letters and periods after an "@". Use optionPattern to match subdomains if present. If a subdomain is not present, optionalPattern does not prevent a match if other conditions of pat are met. Extract the pattern.

emails = ["Sue_B@nonprofit.org" "JohnDRoc12@business.com" "R.Franklin@biology.university.org"]; pat = lookBehindBoundary("@") + optionalPattern(lettersPattern + ".") + lettersPattern + "." + lettersPattern; domains = extract(emails,pat)

domains = 3×1 string "nonprofit.org" "business.com" "biology.university.org"

Input Arguments

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Input pattern, specified as a pattern, string array, character vector, or cell array of character vectors.

Data Types: char | string | pattern | cell

Output Arguments

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Output pattern, returned as a pattern or an array of pattern objects.

Extended Capabilities

Version History

Introduced in R2020b