"in" and "not in" in Java

Question

I'm new in java and I was wonder if there is a way to check one string against another string, I've done it in Python like this"

text = "Tree"
if "re" in text:
    print "yes, there is re exist in Tree"

do we have such way in java to check one sting if exist in another string?

Edit: I used String as an example, i was mainly looking for such function like how python has, as i mention in my caption "in" and "not in" in java, to compare any variable that exist within another variables.

in python i can compare array or list vs single String variable:

myList = ["Apple", "Tree"]
if "Apple" in myList:
    print "yes, Apple exist"

even array vs array:

myList = ["Apple", "Tree","Seed"]
if ["Apple","Seed"] in myList:
    print "yes, there is Apple and Seed in your list"

and single Integer vs array:

myNumber = [10, 5, 3]
if 10 in myNumber:
    print "yes, There is 10"

I was mainly looking for function that if java provide so it can speed up the variables comparison.

@Eran no i didn't check String class, cause in python there is "in" and "not in" to compare **any value** (not only string), it can even check array, number and etc... — Bear, May 01 '16 at 12:50

uwolfer · Answer 1 · 2016-05-01T11:53:35.063

6

String#contains is what you are looking for.

String text = "Tree";
if (text.contains("re")) {
    System.out.println("yes, there is re exist in Tree");
}

Alternatives:

String#indexOf

String text = "Tree";
if (text.indexOf("re") != -1) {
    System.out.println("yes, there is re exist in Tree");
}

String#matches

String text = "Tree";
if (text.matches(".*re.*")) {
    System.out.println("yes, there is re exist in Tree");
}

Pattern

String text = "Tree";
if (Pattern.compile(".*re.*").matcher(text).find()) {
    System.out.println("yes, there is re exist in Tree");
}

edited May 01 '16 at 11:53

answered May 01 '16 at 11:01

uwolfer

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1

I have added some alternatives above which can be useful in other (a bit more complicated) usecases. – uwolfer May 01 '16 at 11:58
thanks for reply, that is very helpful, but i'm mainly looking for function built in java to compare different type of variables like how python does with "in" and "not in", cause i notice since in java we have already define the variables unlike python, so it should be much more faster and easier to compare the variables. – Bear May 01 '16 at 13:17

Adnan Isajbegovic · Answer 2 · 2016-05-02T08:56:16.387

2

There is:

boolean isInString = fullString.contains(subString);

Update for new question:

If you want to check if string is in given array, you have Arrays class for that:

Arrays.asList(givenArrayOfStrings).contains(yourString)

Note: for your specific created objects, you must implement method equals() in order to use this.

edited May 02 '16 at 08:56

answered May 01 '16 at 11:02

Adnan Isajbegovic

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score 0 · Answer 3 · answered May 01 '16 at 11:06

You can have at least 2 ways to do that in java:

public static void main(String[] args) {
    String text = "Tree";

    // option 1: index of... returns -1 if not present
    System.out.println(text.indexOf("re"));

    // option 2: contains
    System.out.println(text.contains("re"));
}

score 0 · Answer 4 · edited May 01 '16 at 12:08

0

You can simply check this using the contains() method of the String class.

String s = "answer";
if(s.contains("ans")) {
    System.out.print("Yes");
}

edited May 01 '16 at 12:08

bcsb1001

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answered May 01 '16 at 11:09

ambar003

5
4

score 0 · Answer 5 · answered May 01 '16 at 11:35

Simple way of doing this in java as follows

class StringTest { // Class
    public static void main(String[] args) { // Main method
        String text = "Tree";
        if (text.contains("re")) { // Checking
            System.out.println("yes, there is re exist in Tree");
        }
    }
}

"in" and "not in" in Java

5 Answers5