Extracting lines containing a word from a Java string using regex

Question

I have a problem with the following code. I want to extract the lines containing the word attribute. I've used http://www.regextester.com/ where this seems to work just fine, but in my program the string remains intact. I don't get why. Could it be that it doesn't use the newline characters correctly, so the ^ and $ get the entire string?

Here's the code:

String attributes = VS.replaceAll("^(?!attribute).*$", "");

And here's the string:

    String vShaderStr = 
        "attribute vec4 a_position;                                             \n"
        +"attribute vec3 a_normal;                                              \n"
        +"attribute vec2 a_texCoord;                                            \n"
        +"uniform mat4 modelViewMatrix;                                         \n"
        +"uniform mat4 projectionMatrix;                                        \n"
        +"void main()                                                           \n"
        +"{                                                                     \n"
        +"      gl_Position = projectionMatrix * modelViewMatrix * a_position;  \n"
        +"}                                                                     \n";

Thanks a lot!

Kilian Foth · Accepted Answer · 2011-08-13 16:17:35Z

2

Yes, ^ and $ match only the start and end of a String, not of a \n-terminated line within a String. You need to compile your regex with the flag MULTILINE to change that. So the solution is to start your regex specification with (?m) .

answered Aug 13, 2011 at 16:17

Kilian Foth

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1 Comment

user481572 Over a year ago

Kilian is correct, can't paste my unit test in here, but just change your regex line to String attributes = VS.replaceAll("(?m)^(?!attribute).*$", ""); as Kilian said

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