Php regular escape $ symbol. does a slash work?

{Code...} does not match, but it works with two slashes.

$ Pattern = "// \{\$/"; preg_match ($ pattern, $ this-> content, $ matches); var_dump ($ matches)

No matching
But it works with two slashes.

Reply content:

$ Pattern = "// \{\$/"; preg_match ($ pattern, $ this-> content, $ matches); var_dump ($ matches)

No matching
But it works with two slashes.

Because variables are parsed in double quotes in PHP, you can replace them with single quotes or add.

$ Pattern = "/\ {\ $ var/"; // $ var variable $ pattern = '/\ {\ $ /';

In the string\It is used as an escape character, so it is represented in a string.\Need to use\\. Therefore$In fact, two conversion is required, that is\ $.

A single string\Is a need that cannot be correctly identified\\
I have already explained it in detail.
$ Pattern = "/\\{\$ /";