[bazoom42]

Complexity in the standard library is not that relevant. If you make your own custom dictionary implementation, you increase complexity of your code base compared to just using the one in the standard library, even if your own implementaion is simpler.

The relevant complexity for using a regex is the complexity of the pattern itself and the complexity of invoking the regex. Any custom procedural solution will be more complex unless it is literally something as simple as checking whether a string contain a given literal string.

[rerdavies]

For some arbitrary definition of complex.