alphanumericBoundary

Match boundary between alphanumeric and non-alphanumeric characters

Since R2020b

Syntax

pat = alphanumericBoundary

pat = alphanumericBoundary(type)

Description

pat = alphanumericBoundary creates a pattern that matches the start or end of a run of letters and numbers. alphanumericBoundary can be negated using the ~ operator. When negated, ~alphanumericBoundary matches the boundary between any two characters except at the start or end of a run of alphanumerics.

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

Examples

Match Boundaries of Letters and Digits

Use alphanumericBoundary to divide text along boundaries between letters and digits and non-alphanumeric characters.

txt = "123abc .?! def456";
pat = alphanumericBoundary;

Use replace to insert "|" characters at the matched boundaries. This operation shows where these boundaries are in the text that contains a variety of character types.

replace(txt,pat,"|")

ans = 
"|123abc| .?! |def456|"

Match Start and End Boundaries of Letters and Digits

Use the "start" and "end" options for alphanumericBoundary to match the boundary between letters and digits and non-alphanumeric characters.

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

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

Extract the pattern.

boundaries = extract(txt,pat)

boundaries = 4x1 string
    "123"
    "abc"
    "def"
    "456"

Negating Boundaries of Letters and Digits

Use the ~ operator to negate alphanumericBoundary. This pattern matches the boundary between two characters when both are alphanumeric characters or neither character is alphanumeric.

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

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

Use replace to insert "|" characters to show where ~alphanumericBoundary 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.

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