Better way to detect if a string contains multiple words

Question

I am trying to create a program that detects if multiple words are in a string as fast as possible, and if so, executes a behavior. Preferably, I would like it to detect the order of these words too but only if this can be done fast. So far, this is what I have done:

if (input.contains("adsf") && input.contains("qwer")) {     execute();           } 

As you can see, doing this for multiple words would become tiresome. Is this the only way or is there a better way of detecting multiple substrings? And is there any way of detecting order?

Answer 1

I'd create a regular expression from the words:

Pattern pattern = Pattern.compile("(?=.*adsf)(?=.*qwer)"); if (pattern.matcher(input).find()) {     execute(); } 

For more details, see this answer: https://stackoverflow.com/a/470602/660143

Answer 2

Editors note: Despite being heavily upvoted and accepted, this does not function the same as the code in the question. execute is called on the first match, like a logical OR.

You could use an array:

String[] matches = new String[] {"adsf", "qwer"};  bool found = false; for (String s : matches) {   if (input.contains(s))   {     execute();     break;   } } 

This is efficient as the one posted by you but more maintainable. Looking for a more efficient solution sounds like a micro optimization that should be ignored until proven to be effectively a bottleneck of your code, in any case with a huge string set the solution could be a trie.