regexptranslate

Translate a special character in a character vector using the regexptranslate function. Then use the result as a regular expression in regexp.

Create a character vector that contains the characters '\n'.

chr = 'The sequence \n generates a new line.'

chr = 
'The sequence \n generates a new line.'

Create a regular expression that finds '\n' as a sequence of the two consecutive characters '\' and 'n'. Since the regexp function interprets '\n' as a newline character, use regexptranslate to create a regular expression to escape '\n'.

pattern = regexptranslate('escape','\n')

pattern = 
'\\n'

Find the starting index of '\n' in chr. To prevent regexp from interpreting '\n' as a newline, use pattern as the regular expression.

idx = regexp(chr,pattern)

idx = 
14

Call regexp without escaping '\n'. Since regexp interprets '\n' as a newline, it does not find the literal characters in chr. The regexp function returns an empty array when it does not find a match.

idx = regexp(chr,'\n')

idx =

     []

Create a string.

str = "Put your money in."

str = 
"Put your money in."

Specify the text, '$0.02', as the text to replace the word 'money'. To escape the '$' and '.' characters, use regexptranslate.

r = regexptranslate('escape','$0.02')

r = 
'\$0\.02'

Replace 'money' using the regexprep function.

newStr = regexprep(str,'money',r)

newStr = 
"Put your $0.02 in."

Create a string array that contains file names. Then find only the file names that end with '.mat'.

str = ["test1.mat","myfile.mat","my-matlab-script.m", ...
       "jan30.mat","table3.xls"]

str = 1×5 string
    "test1.mat"    "myfile.mat"    "my-matlab-script.m"    "jan30.mat"    "table3.xls"

To match strings with a regular expression, specify '*.mat' as the regular expression. Then translate the wildcard character, '*', using the regexptranslate function.

pattern = regexptranslate('wildcard','*.mat')

pattern = 
'.*\.mat'

Find matching elements in str using the regular expression specified by pattern.

matches = regexp(str,pattern)

matches=1×5 cell array
    {[1]}    {[1]}    {0×0 double}    {[1]}    {0×0 double}

Create a logical array, TF, that contains 1 where corresponding elements of str matched pattern. Then index into str using TF to display the file names that end with '.mat'.

tf = ~cellfun('isempty',matches);
newStr = str(tf)

newStr = 1×3 string
    "test1.mat"    "myfile.mat"    "jan30.mat"

Create a character vector that contains words separated by whitespace characters, such as spaces and newline characters.

chr = 'Whose woods these are I think I know.';
chr = [chr newline 'His house is in the village though']

chr = 
    'Whose woods these are I think I know.
     His house is in the village though'

Specify '\s' as a regular expression that matches whitespace characters. Then replace those characters in chr.

expression = '\s';
newChr = regexptranslate('flexible',chr,expression)

newChr = 
'Whose\swoods\sthese\sare\sI\sthink\sI\sknow.\sHis\shouse\sis\sin\sthe\svillage\sthough'