CODEWITHSUNDEEP
java
Floyd Bostan
Floyd Bostan

Reputation: 141

What does the colon mean in Java?

What does the colon mean in Java? I have this:

public static List<String> findAllAnagrams(List<String> words) {
    List<String> result = new LinkedList<String>();
    for(String i : words){
        for (String j : words){
            if (result.contains(i)) {
                break;
            }
            else if (i == j) {

            } else {
                if (areAnagrams(i,j)){
                    result.add(i);
                    System.out.println(result);
                }
            }
        }
    }          
    return result;
}

Upvotes: 12

Views: 60483

Answers (5)

Abraham
Abraham

Reputation: 603

It means one thing, it is an enhanced for loop.

for (String i: words)

means the same things as

for (int i = 0; i < words.length; i++) {
    //
}

Joshua Bloch, in Item 46 of his worth reading Effective Java, says the following:

The for-each loop, introduced in release 1.5, gets rid of the clutter and the opportunity for error by hiding the iterator or index variable completely. The resulting idiom applies equally to collections and arrays:

The preferred idiom for iterating over collections and arrays

for (Element e : elements) {
    doSomething(e);
}

When you see the colon (:), read it as “in.” Thus, the loop above reads as “for each element e in elements.” Note that there is no performance penalty for using the for-each loop, even for arrays. In fact, it may offer a slight performance advantage over an ordinary for loop in some circumstances, as it computes the limit of the array index only once. While you can do this by hand (Item 45), programmers don’t always do so.

Upvotes: 12

Nenad Bulatović
Nenad Bulatović

Reputation: 7434

It is for-each loop. When you see the colon (:) read it as "in" You can find very good explanation in Oracle docs with included examples, here

Upvotes: 0

rai.skumar
rai.skumar

Reputation: 10667

Don't think colon(:) means anything particularly. It's just how Java designers thought to delimit parameter and expression inside improved for loop.

for ( FormalParameter : Expression ) Statement

Check Language specification for same : http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.14.2

Upvotes: 0

TheWhiteRabbit
TheWhiteRabbit

Reputation: 15758

(String i : words)

For each item in words

: to indicate iterator item and item as i

so to answer - it represents for-each loop

Upvotes: 4

Jigar Joshi
Jigar Joshi

Reputation: 240860

colon in for each loop is part of syntax, colon also appears with label

Upvotes: 2

Related Questions