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textBoundary

Match start or end of text

Description

example

pat = 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.

example

pat = textBoundary(type) specifies whether to match at the start or end of text. type can be 'start', 'end', or 'either' (default).

Examples

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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"

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"

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

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Boundary type, specified as 'start', 'end', or 'either'.

Data Types: char | string

Output Arguments

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Pattern expression, returned as a pattern object.

Introduced in R2020b