maskedPattern - Pattern with specified display name - MATLAB (original) (raw)
Pattern with specified display name
Since R2020b
Syntax
Description
[newpat](#mw%5F895e17a3-7ed9-42c6-84ce-11225a7e0070%5Fsep%5Fmw%5F2527cdca-90c8-43b1-8ea8-8fa52700322c) = maskedPattern([pat](#mw%5F895e17a3-7ed9-42c6-84ce-11225a7e0070%5Fsep%5Fmw%5F619a0af2-3091-404f-9c61-e268bcf7fbcb)) creates a pattern that uses the input name of pat when displaying the pattern expression of newpat. You can usemaskedPattern to simplify long, complicated pattern expressions by hiding some of the details in the expression.
[newpat](#mw%5F895e17a3-7ed9-42c6-84ce-11225a7e0070%5Fsep%5Fmw%5F2527cdca-90c8-43b1-8ea8-8fa52700322c) = maskedPattern([pat](#mw%5F895e17a3-7ed9-42c6-84ce-11225a7e0070%5Fsep%5Fmw%5F619a0af2-3091-404f-9c61-e268bcf7fbcb),[mask](#mw%5F4a453aac-3e19-4ed5-a70c-22958d9286d1)) specifies a name to display, mask, when displaying the pattern expression of newpat.
Examples
Hide Details When Displaying Complicated Patterns
Use maskedPattern to display a variable in place of a complicated pattern expression.
Build a pattern that matches simple arithmetic expressions composed of numbers and arithmetic operators.
mathSymbols = asManyOfPattern(digitsPattern | characterListPattern("+-*/="),1)
mathSymbols = pattern Matching:
asManyOfPattern(digitsPattern | characterListPattern("+-*/="),1)Build a pattern that matches arithmetic expressions with whitespaces between characters using mathSymbols.
longExpressionPat = asManyOfPattern(mathSymbols + whitespacePattern) + mathSymbols
longExpressionPat = pattern Matching:
asManyOfPattern(asManyOfPattern(digitsPattern | characterListPattern("+-*/="),1) + whitespacePattern) + asManyOfPattern(digitsPattern | characterListPattern("+-*/="),1)The displayed pattern expression is long and difficult to read. Use maskedPattern to display the variable name, mathSymbols, in place of the pattern expression.
mathSymbols = maskedPattern(mathSymbols); shortExpressionPat = asManyOfPattern(mathSymbols + whitespacePattern) + mathSymbols
shortExpressionPat = pattern Matching:
asManyOfPattern(mathSymbols + whitespacePattern) + mathSymbolsUse details to show more information
Create a string containing some arithmetic expressions, and then extract the pattern from the text.
txt = "What is the answer to 1 + 1? Oh, I know! 1 + 1 = 2!"; arithmetic = extract(txt,shortExpressionPat)
arithmetic = 2x1 string "1 + 1" "1 + 1 = 2"
Display Specified Pattern Names
Use maskedPattern to display a specified name for a complicated pattern expression.
Build two patterns: one that matches words that begin and end with the letter D, and one that matches words that begin and end with the letter R.
dWordsPat = letterBoundary + caseInsensitivePattern("d" + lettersPattern + "d") + letterBoundary; rWordsPat = letterBoundary + caseInsensitivePattern("r" + lettersPattern + "r") + letterBoundary;
Use maskedPattern to display a specified name in place of the pattern expressions. Build a pattern using the masked patterns that find words that start and end with D followed by a word that starts and ends with R.
dWordsPat = maskedPattern(dWordsPat,"Words that start and end with D"); rWordsPat = maskedPattern(rWordsPat,"Words that start and end with R"); dAndRWordsPat = dWordsPat + whitespacePattern + rWordsPat
dAndRWordsPat = pattern Matching:
Words that start and end with D + whitespacePattern + Words that start and end with RUse details to show more information
Create a string, and then extract the pattern from the text.
txt = "Dad, look at the divided river!"; words = extract(txt,dAndRWordsPat)
Make Custom Pattern Functions
Create custom pattern functions and usemaskedPattern to hide details.
Create a function atLeastOneOfPattern that takes the input pattern pat and creates a pattern, newPat, that matches one or more consecutive instances of pat. UsemaskedPattern to hide the details of the pattern when displayed.
function newPat = atLeastOneOfPattern(pat) arguments pat pattern end
newPat = asManyOfPattern(pat,1); newPat = maskedPattern(newPat,compose("atLeastOneOfPattern(%s)",pat));
end
Call atLeastOneOfPattern with the input "a" and display newPat.
newPat = atLeastOneOfPattern("a")
newPat =
pattern
Matching:
atLeastOneOfPattern("a")Show all details
Match Hexadecimal Numbers
Create a pattern hexDigit that matches numeric characters from 0-9 and letters from a-f with characterListPattern. Since characterListPattern is case sensitive, use caseInsensitivePattern so that hexDigit matches regardless of character case.
hexDigit = characterListPattern('0','9') | characterListPattern('a','f'); hexDigit = caseInsensitivePattern(hexDigit); hexDigit = maskedPattern(hexDigit)
hexDigit = pattern Matching:
hexDigitUse details to show more information
hexDigit matches individual digits of hexadecimal numbers. Match full hexadecimal numbers by building a pattern that matches the literal text "0x" followed by one or more occurrences of hexDigit.
hexNumberPattern = "0x" + asManyOfPattern(hexDigit, 1)
hexNumberPattern = pattern Matching:
"0x" + asManyOfPattern(hexDigit,1)Use details to show more information
Use this pattern to extract hexadecimal numbers from a string.
hexNumbers = extract("The answer is 0x2A", hexNumberPattern)
Input Arguments
pat — Input pattern
pattern array | string array | character vector | cell array of character vectors
Input pattern, specified as a pattern, string array, character vector, or cell array of character vectors.
Data Types: char | string | pattern | cell
mask — Masked pattern name
string array | character vector | cell array of character vectors
Masked pattern name, specified as a string scalar, character vector, or cell array of character vectors.
Data Types: char | string | cell
Output Arguments
newpat — Output pattern
pattern (default) | array of pattern objects
Output pattern, returned as a pattern or an array of pattern objects.
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