Converting an ereg_replace to preg_replace

Question

I have to convert an ereg_replace to preg_replace

The ereg_replace code is:

ereg_replace( '\$([0-9])', '$\1', $value );

As preg is denoted by a start and end backslash I assume the conversion is:

preg_replace( '\\$([0-9])\', '$\1', $value );

As I don't have a good knowledge of regex I'm not sure if the above is the correct method to use?

Answer 1

One of the differences between ereg_replace() and preg_replace() is that the pattern must be enclosed by delimiters: delimiter + pattern + delimiter. As stated in the documentation, a delimiter can be any non-alphanumeric, non-backslash, non-whitespace character. This means that valid delimiters are: /, #, ~, +, %, @, ! and <>, with the first two being most often used (but this is just my guess).

If your ereg_replace() worked as you expected, then simply add delimiters to the pattern and it will do the thing. All examples below will work:

preg_replace('/\$([0-9])/', '$\1', $value);

or

preg_replace('#\$([0-9])#', '$\1', $value);

or

preg_replace('%\$([0-9])%', '$\1', $value);

Answer 2

Try

preg_replace( '#\$([0-9])#', '\$$1', $value );