How to check if a particular word from a string list contains in a string, but it should not be between any other words?

Question

I need to check if any string from a string list matches wholly (whole word search) within the input string i.e. it should not match the word in between characters. e.g. check the code below:

String input = "i was hoping the number";
String[] valid = new String[] { "nip", "pin" };
if (Arrays.stream(valid).anyMatch(input::contains)) {
    System.out.println("valid");
}

My output is valid, which is not correct. It is fetching the pin string from the hoping word. I should be able to match only if the pin word is separate.

Can you add table with several examples what should match and what should not match and why? — Alexey R., Oct 03 '20 at 13:41
there are more than 2 hundred input data strings so iam fetching each input data and checking if these words are there it should not be present in between any other charcters like pin present in hooping it should be separate — Aiswarya Janarthanan, Oct 03 '20 at 13:48

Arvind Kumar Avinash · Accepted Answer · 2020-10-03T21:09:05.380

0

Do it as follows:

import java.util.Arrays;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        String input = "i was hoping the number";
        String[] valid = new String[] { "nip", "pin" };
        if (Arrays.stream(valid).anyMatch(p -> Pattern.compile("\\b" + p + "\\b").matcher(input).find())) {
            System.out.println("valid");
        }
    }
}

Note that \b is used for word boundary which I have added before and after the matching words to create word boundary for them.

Some more tests:

import java.util.Arrays;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        String[] testStrings = { "i was hoping the number", "my pin is 123", "the word, turnip ends with nip",
                "turnip is a vegetable" };
        String[] valid = new String[] { "nip", "pin" };
        for (String input : testStrings) {
            if (Arrays.stream(valid).anyMatch(p -> Pattern.compile("\\b" + p + "\\b").matcher(input).find())) {
                System.out.println(input + " => " + "valid");
            } else {
                System.out.println(input + " => " + "invalid");
            }
        }
    }
}

Output:

i was hoping the number => invalid
my pin is 123 => valid
the word, turnip ends with nip => valid
turnip is a vegetable => invalid

Solution without using Stream API:

import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        String input = "i was hoping the number";
        String[] valid = new String[] { "nip", "pin" };
        for (String toBeMatched : valid) {
            if (Pattern.compile("\\b" + toBeMatched + "\\b").matcher(input).find()) {
                System.out.println("valid");
            }
        }
    }
}

edited Oct 03 '20 at 21:09

answered Oct 03 '20 at 13:47

Arvind Kumar Avinash

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Hi , if i give equals it is checking for an entire input string but the keyword pin is somewhere in the string so for valid scenarios im getting nothing.kindly help – Aiswarya Janarthanan Oct 03 '20 at 14:29
It should check the keword pin in the strong but not between characters – Aiswarya Janarthanan Oct 03 '20 at 14:30
eg: my pin is 1234 it is valid – Aiswarya Janarthanan Oct 03 '20 at 14:30
hoping 1234 is invalid – Aiswarya Janarthanan Oct 03 '20 at 14:30
it is invalid if i give i was hoping pin the number – Aiswarya Janarthanan Oct 03 '20 at 14:32
@AiswaryaJanarthanan - I've added some more tests. Let me know if they meet your criteria or not. Also, I would like to understand why `i was hoping pin the number` is invalid. As per your requirement, it should be valid as it contains `pin` as a separate word - isn't it? – Arvind Kumar Avinash Oct 03 '20 at 14:39
Hi , the string i was hoping the pin number is valid but in my logic im getting invalid which is incorrect – Aiswarya Janarthanan Oct 03 '20 at 16:26
in your test case this particular line if (Arrays.stream(valid).anyMatch(p -> Pattern.compile("\\b" + p + "\\b").matcher(input).find())) is throwing an error as input should be declared as final which i cant make it iam changing the input string in between – Aiswarya Janarthanan Oct 03 '20 at 16:27
the error is input string defined in enclosing scope must be final or effectively final – Aiswarya Janarthanan Oct 03 '20 at 16:28
@AiswaryaJanarthanan - I wrote the solution using the `Stream` API because you had used it in your question. I believe you already know that `input` needs to be final in case of `Stream`. If you want, I can write another solution without using `Stream` API. – Arvind Kumar Avinash Oct 03 '20 at 16:30
yeah that would be great , thank you so much for helping me with this – Aiswarya Janarthanan Oct 03 '20 at 16:35
@AiswaryaJanarthananv - I hope, the non-Stream solution works for you. Feel free to comment in case of any further doubt/issue. – Arvind Kumar Avinash Oct 03 '20 at 16:40

How to check if a particular word from a string list contains in a string, but it should not be between any other words?

1 Answers1