Find Alphanumeric characters in string & split by it

Question

I need a method to split the string by alphanumeric characters,

Example-

String str = 'is this testing?yes it is.Please split the string, then use for further functionality.';

I need list of string as below as below,

is this testing

yes it is

Please split the string

then use for further functionality

Also i want to keep the record of characters by which it is split to construct the string back to the original

Answer 1

I think you mean punctuation characters. I've picked a few that you might use for this example.

String hey = 'here is some stuff. Punctuation is the thing! Yes, split on that';
String[] strings = hey.split('[,.\\!\\:\\?]');
For (String s : strings){
    System.debug(s);
}

As you can see, the split expression is a regular expression. This is the reason for the escaping of these characters eg \\! in the expression.

To be able to reconstruct the string, you could use the strings array to replace matching strings in the source string with a token. Then when you want to reconstruct, just replace the tokens with the your phrases in the strings array.

For example:

String hey = 'hey, there is ? a lot: of bits of, punctuation. here!!';
System.debug(hey);

String[] strings = hey.split('[,.\\!\\:\\?]');
System.debug(strings);

//replace matched strings with empty
for (String fragment : strings ){
        hey = hey.replace(fragment,'__fragment__');
}

for (String fragment : strings){
    hey = hey.replaceFirst('__fragment__',fragment);
}
System.debug(hey);