preg_match RegExp in beginning, inside or end of word

Question

I'm very new to this regular expression bit.

I've been trying these online services but at loss.

I need it explained to me how to write a pattern that match deroot, derooted, rooted and root anywhere in string when searching for 'root'

Answer 1

preg_match("/root/s", $input_line, $output_array);

you can use this to find any string that contains root .

demo here : http://www.phpliveregex.com/p/4v0

Answer 2

Pattern is pretty simple:

/(root)/

You can add some modifiers i, g, m:

/(root)/i // for case-insensitive search