ubb text editing, preg_replace($pattern,$replace,$stirng);
I read in the manual that \\1 and $1 are the same.
Original words from the manual: Replacement can contain back references \\n or $n, and the latter is preferred grammatically. Each such reference will be replaced by the text captured by the matching nth capturing subgroup. n can be 0-99, \\0 and $0 represent the complete pattern matching text. The serial number counting method of capturing subgroups is: the left bracket representing the capturing subgroup is counted from left to right, starting from 1. If you want to use backslashes in replacement, you must use 4 ("\\\\", translator's annotation: Because this is first a PHP string, after escaping, there are two, and then after passing through the regular expression engine is considered a text backslash).
