whitespaceBoundary

Match boundary between whitespace characters and non-whitespace characters

Syntax

pat = whitespaceBoundary

pat = whitespaceBoundary(type)

Description

pat = whitespaceBoundary creates a pattern that matches the start or end of a run of whitespace characters. whitespaceBoundary can be negated using the ~ operator. When negated, ~whitespaceBoundary matches the boundary between any two characters except at the start or end of a run of whitespaces.

pat = whitespaceBoundary(type) specifies whether to match at the start or end of a run of whitespaces. type can be 'start', 'end', or 'either' (default).

Examples

Match Boundaries of Whitespaces

Use whitespaceBoundary to divide a string along whitespace boundaries. This pattern matches boundaries between a whitespace character and a non-whitespace character.

Create a pattern that matches any whitespace boundaries.

txt = "123 abc .?! def 456";
pat = whitespaceBoundary ;

Use replace to insert "|" characters at the matched boundaries.

replace(txt,pat,"|")

ans = 
"123| |abc| |.?!| |def| |456"

Match Start and End Boundaries of Whitespaces

Use the "start" and "end" options for whitespaceBoundary to match the boundary between whitespaces and non-whitespace characters.

Create a string that contains several different character types. Create a pattern that matches any characters between an "end" boundary of whitespaces and a "start" boundary.

txt = "123 abc .?! def 456";
pat = whitespaceBoundary("end") + wildcardPattern(1,inf) + whitespaceBoundary("start");

Extract the pattern.

boundaries = extract(txt,pat)

boundaries = 3x1 string
    "abc"
    ".?!"
    "def"

Negating Boundaries of Whitespaces

Use the ~ operator to negate whitespaceBoundary. This matches boundaries between two characters when both are whitespace characters or neither is a whitespace character.

Create a string that contains several different character types. Create a pattern that matches a negated whitespaceBoundary.

txt = "123 abc .?!";
pat = ~whitespaceBoundary;

Use replace to insert "|" characters to show where ~whitespaceBoundary matches.

boundaries = replace(txt,pat,"|")

boundaries = 
"|1|2|3 a|b|c .|?|!|"

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.

More About

Definitions

A whitespace is any character or series of characters that represent horizontal or vertical space. When rendered, a whitespace character does not correspond to a visible mark, but typically does occupy an area on a page. Common whitespace characters include:

Significant Whitespace Character	Description
char(32)	Standard whitespace character, ' '
char(133)	Next line
char(160)	Nonbreaking space
char(8199)	Figure space
char(8239)	Narrow no-break space

For more information, see Whitespace character.

Version History

Introduced in R2020b