How do I do a case-insensitive replace all for a string?

Question

I've got a project where I'd like to replicate some of the internal merge field functionality so users can build a link and it'd be really helpful if I could do a case-insensitive string replaceAll.

For example, if I want to replace {!id} or any of it's case variations I could do

return input.replaceAll('\\{![iI][dD]}\\', value);

While I can make do with creating a function to built a regex for any particular input pattern (nevermind the potential issues with script statements) it'd be great if I could emulate how sed works (the 'i' indicates case insensitive). For example:

sed 's/\{!id\}/replacement/i' inputfile.txt

Anyone have any tips on how to accomplish this?

Answer 1

The option to replace case insensitive regex in java is Pattern.CASE_INSENSITIVE, which can also be specified as (?i)

(http://boards.developerforce.com/t5/Apex-Code-Development/Why-Pattern-CASE-INSENSITIVE-not-detectable/td-p/204337)

String srcStr = '{!id} value {!Id} is not {!ID}';
String replaceToken = '(?i)\\{!id\\}';
System.debug('REPLACEMENT ' + srcStr.replaceAll(replaceToken, ''));
System.assertEquals('  value  is not ', srcStr.replaceAll(replaceToken, ''));

Answer 2

Just curious can you not convert the string to a particular case?

say

String ex = 'Upper';
ex.toLowerCase();

(or)

ex.toUpperCase()

Examples from the official documentation -

String s1 = 'ThIs iS hArD tO rEaD';
System.assertEquals('this is hard to read',
s1.toLowerCase());

String myString1 = 'abcd';
String myString2 = 'ABCD';
myString1 = 
   myString1.toUpperCase();
Boolean result = 
   myString1.equals(myString2);
System.assertEquals(result, true);

Answer 3

You can use other salesforce string methods for the replacement. For example:

String inputString = 'Welcome {!Contact.Name}';
String toReplace = 'contact.name';  //Can use describe methods and get all fields for the relevant object/s

while(inputString.indexOfCaseIgnoreCase(toReplace) != -1){
    Integer indexStartReplace = inputString.indexOfCaseIgnoreCase(toReplace);
    Integer indexEndReplace = indexStartReplace + toReplace.length()
    inputString = inputString.replace(inputString.substring(indexStartReplace, indexEndReplace), '');
}

Answer 4

Salesforce Apex String replacement: Use the following regex to ignore case sensitivity in replace operation.

***//Use (?i) regex to make the replacement process to avoid case sensitive***   
String message = 'Welcome Home';
String searchText = 'home';
String newText = 'World';     
               
String convertedText = message.replaceAll('(?i)'+searchText, newText); 
System.debug('convertedText>> '+ convertedText);
***//Output: convertedText>> Welcome World***