Regex find word in the string

Question

In general terms I want to find in the string some substring but only if it is contained there.

I had expression :

^.*(\\bpass\\b)?.*$

Answer 1

A period only matches a single character, so you're

^.(\bpass\b)?.$

is matching:

• Start of input
• A single character
• Optionally
  • Word boundary
  • "pass"
  • Word boundary
• Single char
• End of input

which I would not expect to match "high pass h3" at all.

The regular expression:

pass

(no metacharacters) will match any string containing "pass" (but then so would a "find string in string" function, and this would probably be quicker without the complexities of a regex).