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;
}
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.
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;
}
}
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]));
}
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.
Split with non-digits, then parse the result:
List<Integer> response = Arrays.stream(line.split("\\D+"))
.filter(s -> !s.isBlank())
.map(Integer::parseInt)
.toList();
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]
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);
}
}
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
}
