how to check whether a string contains words specified in a set

Question

how to check whether a string contains any element specified in a set of elements? say for eg: how to check whether below statement 'I got two dogs and a cat'

contains words specified in set {dog,cat,parrot}

Answer 1

You can use the Pattern and Matcher class, constructing the regexp pattern from the values of the set, or you could loop through each value in the set and compare it to a value. Solutions are ordered from most flexible to least flexible.

Pattern and Matcher

Pattern p = Pattern.compile(String.join(new List<String>(keyWords),'|'));
Matcher m = p.matcher(targetString);
if(m.find()) { ... }

• Can be modified to match whole words only, can be made case insensitive, and isn't affected by punctuation.

Search and Compare

Boolean matches = false;
for(String key:keyWords) {
    if(targetString.indexOf(key)>-1) {
        matches = true;
        break;
    }
}

• Matches any part of any word; matching whole words would be rather difficult without a complex condition statement.

Answer 2

 String test='There are two dogs and a cat';
 set<string> a=new Set<string>{'dog','cat','pat'};
 boolean check=false;

List<String> lsttest=test.split(' ');

 for(String s: lsttest){
    if(a.contains(s)){
    check=true;
           break;
        }
    }

 system.debug('check...'+check);

You can use the above also to find whether string contains any word

Answer 3

The following code works pretty well without any loop :

Set<String> keyWords = new Set<String>{'dog','cat','pat'};
if(JSON.serialize(keyWords).contains('dog'))
{
    System.debug('It contains dog!');
}