Copying only files without a special string in filename

Question

I have to copy only files from a folder that don't have following string in its filename: NNNNxNNNN (a 3 or 4 digit number followed by the character x followed by a 3 or 4 digit number again -> it's the resolution of an image in the filename)

I'm trying for about an hour with the "find" command but it never does what it should do.

Answer 1

find -E dir_x -type f -not -regex ".*[0-9]{3,4}x[0-9]{3,4}.*" -exec cp {} dir_y \;