CODEWITHSUNDEEP
javaarraysregexstringextract
Dusernajder
Dusernajder

Reputation: 101

Extracting integers from a String into an Array

I need to extract integers from a String into an array.

I've already got the integers, but I wasn't able to place them into an array.

public static void main(String[] args) {
    String line = "First number 10, Second number 25, Third number 123";
    String numbersLine = line.replaceAll("[^0-9]+", "");
    int result = Integer.parseInt(numbersLine);

    // What I want to get:
    // array[0] = 10;
    // array[1] = 25;
    // array[2] = 123;
}

Upvotes: 1

Views: 7197

Answers (8)

Arvind Kumar Avinash
Arvind Kumar Avinash

Reputation: 78975

Extract the integer strings using the pattern, \d+ (i.e. one or more digits) and map them into integers using Integer#parseInt.

int[] array = Pattern.compile("\\d+")
                     .matcher(line)
                     .results()
                     .map(MatchResult::group)
                     .mapToInt(Integer::parseInt)
                     .toArray();

Demo:

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

public class Main {
    public static void main(String[] args) {

        String line = "First number 10, Second number 25, Third number 123";
        
        int[] array = Pattern.compile("\\d+")
                        .matcher(line)
                        .results()
                        .map(MatchResult::group)
                        .mapToInt(Integer::parseInt)
                        .toArray();

        System.out.println(Arrays.toString(array));

    }
}

Output:

[10, 25, 123]

Upvotes: 1

Youcef LAIDANI
Youcef LAIDANI

Reputation: 59950

Split with non-digits, then parse the result:

List<Integer> response = Arrays.stream(line.split("\\D+"))
        .filter(s -> !s.isBlank())
        .map(Integer::parseInt)
        .toList();

Upvotes: 1

Rahul Ramamoorthy
Rahul Ramamoorthy

Reputation: 31

Working code:

public static void main(String[] args) 
{
    String line = "First number 10, Second number 25, Third number 123 ";
    String[] strArray= line.split(",");
    int[] integerArray =new int[strArray.length];

    for(int i=0;i<strArray.length;i++)
        integerArray[i]=Integer.parseInt(strArray[i].replaceAll("[^0-9]", ""));
    for(int i=0;i<integerArray.length;i++)
        System.out.println(integerArray[i]);
        //10
        //15 
        //123
}

Upvotes: 0

Glains
Glains

Reputation: 2863

You can use a regular expression to extract numbers:

String s = "First number 10, Second number 25, Third number 123 ";
Matcher matcher = Pattern.compile("\\d+").matcher(s);

List<Integer> numbers = new ArrayList<>();
while (matcher.find()) {
    numbers.add(Integer.valueOf(matcher.group()));
}

\d+ stands for any digit repeated one or more times.

If you loop over the output, you will get:

numbers.forEach(System.out::println);

// 10
// 25
// 123

Note: This solution does only work for Integer, but that is also your requirement.

Upvotes: 4

dbl
dbl

Reputation: 1109

You could try using the stream api:

String input = "First number 10, Second number 25, Third number 123";

int[] anArray = Arrays.stream(input.split(",? "))
    .map(s -> {
        try {
            return Integer.valueOf(s);
        } catch (NumberFormatException ignored) {
            return null;
        }
    })
    .filter(Objects::nonNull)
    .mapToInt(x -> x)
    .toArray();


System.out.println(Arrays.toString(anArray));

and the output is :

[10, 25, 123]

And the regex.replaceAll version will be:

int[] a = Arrays.stream(input.replaceAll("[^0-9]+", " ").split(" "))
    .filter(x -> !x.equals(""))
    .map(Integer::valueOf)
    .mapToInt(x -> x)
    .toArray();

where output is the same.

Upvotes: 1

odur37
odur37

Reputation: 41

Given you have the numbers a string like "10, 20, 30", you can use the following:

String numbers = "10, 20, 30";

String[] numArray = nums.split(", ");

ArrayList<Integer> integerList = new ArrayList<>();

for (int i = 0; i < x.length; i++) {
    integerList.add(Integer.parseInt(numArray[i]));
}

Upvotes: 1

Pavan Andhukuri
Pavan Andhukuri

Reputation: 1617

Instead of replacing characters with empty string, replace with a space. And then split over it.

import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        String line = "First number 10, Second number 25, Third number 123 ";
        String numbersLine = line.replaceAll("[^0-9]+", " ");

        String[] strArray = numbersLine.split(" ");

        List<Integer> intArrayList = new ArrayList<>();

        for (String string : strArray) {
            if (!string.equals("")) {
                System.out.println(string);
                intArrayList.add(Integer.parseInt(string));
            }
        }

        // what I want to get:
        // int[0] array = 10;
        // int[1] array = 25;
        // int[2] array = 123;
    }
}

Upvotes: 1

Tanu Garg
Tanu Garg

Reputation: 3067

public static void main(String args[]) {

        String line = "First number 10, Second number 25, Third number 123 ";

        String[] aa=line.split(",");
        for(String a:aa)
        {
            String numbersLine = a.replaceAll("[^0-9]+", "");
            int result = Integer.parseInt(numbersLine);
            System.out.println(result);

        }

}

Upvotes: 0

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