Replace multiple newlines, tabs, and spaces

Question

I want to replace multiple newline characters with one newline character, and multiple spaces with a single space.

I tried preg_replace(\"/\\n\\n+/\", \"\\n\",

Answer 1

You need the multiline modifier to match multiple lines:

preg_replace("/PATTERN/m", "REPLACE", $text);

Also in your example you seem to be replacing 2+ newlines with exactly 2, which isn't what your question indicates.