Ignoring the line break in regex?

Question

I have below content in text file

  some texting content   Test

I read it from

Answer 1

You need to use Pattern.DOTALL mode.

replaceAll() doesn't take mode flags as a separate argument, but you can enable them in the expression as follows:

expectedString = inputString.replaceAll("(?s)\\<img.*?cid:part123.*?>", ...);

Note, however, that it's not a good idea to parse HTML with regular expressions. It would be better to use HTML parser instead.

Answer 2

By default, the . character will not match newline characters. You can enable this behavior by specifying the Pattern.DOTALL flag. In String.replaceAll(), you do this by attaching a (?s) to the front of your pattern:

expectedString = inputString.replaceAll("(?s)\\<img.*?cid:part123.*?>", 
    "NewContent");

See also Pattern.DOTALL with String.replaceAll

Answer 3

If you want your dot (.) to match newline also, you can use Pattern.DOTALL flag. Alternativey, in case of String.replaceAll(), you can add a (?s) at the start of the pattern, which is equivalent to this flag.

From the Pattern.DOTALL - JavaDoc : -

Dotall mode can also be enabled via the embedded flag expression (?s). (The s is a mnemonic for "single-line" mode, which is what this is called in Perl.)

So, you can modify your pattern like this: -

expectedStr = inputString.replaceAll("(?s)<img.*?cid:part123.*?>", "Content");

NOTE: - You don't need to escape your angular bracket(<).