textBoundary - Match start or end of text - MATLAB (original) (raw)
Main Content
Match start or end of text
Since R2020b
Syntax
Description
[pat](#mw%5F31a2088b-3c95-4798-b029-c2952b35b0f6%5Fsep%5Fmw%5F5d8462f7-c5cb-4493-9ed2-15c426e9be6f) = textBoundary creates a pattern that matches the start or end of text. textBoundary can be negated using the~ operator. When negated, textBoundary matches between every character except at the start or end of the text.
[pat](#mw%5F31a2088b-3c95-4798-b029-c2952b35b0f6%5Fsep%5Fmw%5F5d8462f7-c5cb-4493-9ed2-15c426e9be6f) = textBoundary([type](#mw%5F31a2088b-3c95-4798-b029-c2952b35b0f6%5Fsep%5Fmw%5F3db4ca55-65f2-47cb-817d-7df607c4d0ee)) specifies whether to match at the start or end of text. type can be'start', 'end', or 'either' (default).
Examples
Match Boundaries of Text
Use textBoundary to match the start or end of text.
Create a string array with multiple pieces of text. Create a pattern that matches the first word of each piece of text.
txts = ["This is the first piece of text" "Here is the second" "Now there are three"]; pat = textBoundary + lettersPattern;
Extract the pattern.
firstWords = extract(txts,pat)
firstWords = 3x1 string "This" "Here" "Now"
Match End Boundaries of Text
Use the "end" option for textBoundary to match the specified endpoint of a piece of text.
Create a string array with multiple pieces of text. Create a pattern that matches the last word of each piece of text.
txts = ["This is the first piece of text" "Here is the second" "Now there are three"]; pat = lettersPattern + textBoundary("end");
Extract the pattern.
lastWords = extract(txts,pat)
lastWords = 3x1 string "text" "second" "three"
Negate Boundaries of Text
Use the ~ operator to negate textBoundary. This matches boundaries between two characters when neither is the start or end of text.
Create a string array with multiple pieces of text. Create a pattern that matches letters that are neither at the start or end of a piece of text.
txts = ["This text is first" "Here is the second" "Now there are three"]; pat = ~textBoundary + lettersPattern + ~textBoundary;
Extract the pattern.
lastWords = extract(txts,pat)
lastWords = 3x4 string "his" "text" "is" "firs" "ere" "is" "the" "secon" "ow" "there" "are" "thre"
Input Arguments
type — Boundary type
'either' (default) | 'start' | 'end'
Boundary type, specified as 'start', 'end', or 'either'.
Data Types: char | string
Output Arguments
pat — Pattern expression
pattern object
Pattern expression, returned as a pattern object.
Extended Capabilities
Thread-Based Environment
Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.
Version History
Introduced in R2020b