Regular Expression: Detect Specific String

Question

I'm trying to search a string in PHP using preg_match(), to return a string that takes the format of 'xdr', where x is a single digit.

The string is otherwise made of characters, numbers, '.' full stops and spaces.

I'm hopeless with regular expressions, can somebody help me out?

I've tried ^([a-zA-Z0-9]+)\s2dr$ but it doesn't work

For example, the string might look like A really big 2.0 was 3dr once

Answer 1

As far as I understand your needs, this regex will work to match a string that contains some number followed by dr:

 /\b\d+dr\b/

in action in preg_match:

preg_match('/\b\d+dr\b/', $string);

explanation:

/      : regex delim
  \b   : word boundary
  \d+  : one or more digit
  dr   : literaly dr
  \b   : word boundary
/      : regex delim

If you want the other characters to be only characters, numbers, '.' full stops and spaces use this:

preg_match('/^[\w\d. ]*\b\d+dr\b[\w\d. ]*$/', $string);

And, to be unicode compatible:

preg_match('/^[\pL\pN. ]*\b\pN+dr\b[\pL\pN. ]*$/', $string);

Answer 2

You're close.

The following regex will match a single digit followed by one or more alpha characters, numbers, full stops and spaces, and ends in dr.

^\d[a-zA-Z0-9. ]+dr$

Note: Not sure if you want the literal dr, if not, drop it from the end.