I am having a problem with this code:
$myvariable = "<?php $user_id = '5'; ?>";
...now I then write it to file using php...
and this is what I see when I open the saved file:
<?php = '5'; ?>
$user_id is missing!
Why is this happening and is there a way to fix this problem?
When you use double-quotes, any $variables in the text will be replaced with their current value. Because $user_id isn't defined in the code that's currently running, it's replaced with nothing.
There are a couple of ways to prevent this from happening. You could wrap your string in single-quotes instead, escaping the existing single-quotes in the text with a backslash:
$myvariable = '<?php $user_id = \'5\'; ?>';
Or you cou could instead escape the $ with a backslash, so that it's not interpreted:
$myvariable = "<?php \$user_id = '5'; ?>";
PHP interprets variables within strings if you surround the string with double-quotes, as you are using. If you use single-quotes, however, it interprets the string literally.
Try escaping the dollar sign in the variable name. Like this:
$myvariable = "<?php \$user_id = '5'; ?>";
"quoted strings, which will happen before you save string to file action.