CODEWITHSUNDEEP
javacollectionshashset
rhanabe
rhanabe

Reputation: 101

Java - how do I check if a string exists in each of the elements of a HashSet

    final HashSet<String> VALUES = new HashSet<String>(Arrays.asList(new String[] {"OK (0.07, 0.05, 0.01)",
            "OK (0.07, 0.05, 0.02)",
            "OK (0.07, 0.05, 0.03)",
            "OK (0.07, 0.05, 0.04)"}));
    String s="OK";
    System.out.println(VALUES.contains(s));

Gives me false. How do I check if "OK" exists in each of the elements?

Upvotes: 2

Views: 7732

Answers (5)

user3153632
user3153632

Reputation: 32

you can test this code:

final HashSet<String> VALUES = new HashSet<String>(Arrays.asList(new String[] {"OK (0.07, 0.05, 0.01)",
                "OK (0.07, 0.05, 0.02)",
                "OK (0.07, 0.05, 0.03)",
                "no (0.07, 0.05, 0.04)"}));
        String s="OK";

        @Test 
        public void teste(){

            for (String a : VALUES) {
                if(a.contains(s)){
                    System.out.println("Ok yes!" + true);
                }else{
                    System.out.println("Don't exist!" + false);
                }
            }

        }

Upvotes: 2

Sibbo
Sibbo

Reputation: 3914

boolean contains = true;
String s = "OK";

for (String str : VALUES) {
    if (!str.conatins(s)) {
        contains = false;
        break;
    }
}

// If contains is true here, every string in the list contains s, otherwise not.

Upvotes: 2

Alexis C.
Alexis C.

Reputation: 93872

Currently, you're checking if your Set contains the value OK. If you want to check if each of the elements of the Set contains OK (note the difference), you'll need to loop through the values of your Set like the others stated.

Using and streams, you can also do :

boolean b = VALUES.stream().allMatch(s -> s.contains("OK"));

Upvotes: 9

Elliott Frisch
Elliott Frisch

Reputation: 201467

You could write a method like contains below to loop over the elements in the Collection.

public static boolean contains(java.util.Collection<String> coll, String s) {
    for (String t : coll) {
        if (t == null) {
            continue;
        }
        if (!t.contains(s)) {
            return false;
        }
    }
    return true;
}

public static void main(String[] args) {
    final HashSet<String> VALUES = new HashSet<String>(Arrays.asList(new String[] {"OK (0.07, 0.05, 0.01)",
            "OK (0.07, 0.05, 0.02)",
            "OK (0.07, 0.05, 0.03)",
            "OK (0.07, 0.05, 0.04)"}));
    System.out.println(contains(VALUES, "OK"));
}

Which outputs true here.

Upvotes: 1

Maroun
Maroun

Reputation: 95978

You should loop on the set and check for every string in it:

for(String st : VALUES) {
    if(!st.contains(s)) { 
       //found string that doesn't contain s
    }
}

Note that now we are using String#contains.

Upvotes: 4

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