Overview
In this tutorial, we show you how to convert an int array to an integer in Java.
Example: int array { 2, 0, 1, 9 } -> 2019
Using For-each loop
package com.jackrutorial;
public class ArrayToIntegers1 {
public static void main(String[] args) {
int intArrs[] = { 2, 0, 1, 9 };
System.out.print("int arrays: [");
for (int i=0; i< intArrs.length; i++) {
System.out.print(intArrs[i]);
if(i < intArrs.length-1) {
System.out.print(",");
}
}
System.out.print("]");
StringBuilder builder = new StringBuilder();
for (int num : intArrs) {
builder.append(num);
}
int number = Integer.parseInt(builder.toString());
System.out.print(" -> converted: ");
System.out.println(number);
}
}
Output
int arrays: [2,0,1,9] -> converted: 2019
The way 2
package com.jackrutorial;
public class ArrayToIntegers2 {
public static void main(String[] args) {
int intArrs[] = {2, 0, 1, 9};
System.out.print("int arrays: [");
for (int i=0; i< intArrs.length; i++) {
System.out.print(intArrs[i]);
if(i < intArrs.length-1) {
System.out.print(",");
}
}
System.out.print("]");
int numberConverted = 0;
for (int number : intArrs) {
numberConverted = 10*numberConverted + number;
}
System.out.print(" -> converted: ");
System.out.println(numberConverted);
}
}
Output
int arrays: [2,0,1,9] -> converted: 2019
The way 3
package com.jackrutorial;
public class ArrayToIntegers3 {
public static void main(String[] args) {
int intArrs[] = {2, 0, 1, 9};
System.out.print("int arrays: [");
for (int i=0; i< intArrs.length; i++) {
System.out.print(intArrs[i]);
if(i < intArrs.length-1) {
System.out.print(",");
}
}
System.out.print("]");
int numberConverted = 0;
for(int i = 0; i < intArrs.length; i++){
numberConverted += intArrs[i]*Math.pow(10,intArrs.length-i-1);
}
System.out.print(" -> converted: ");
System.out.println(numberConverted);
}
}
Output
int arrays: [2,0,1,9] -> converted: 2019
The way 4
package com.jackrutorial;
import org.apache.commons.lang.StringUtils;
public class ArrayToIntegers4 {
public static void main(String[] args) {
Integer intArrs[] = { 2, 0, 1, 9 };
System.out.print("int arrays: [");
for (int i = 0; i < intArrs.length; i++) {
System.out.print(intArrs[i]);
if (i < intArrs.length - 1) {
System.out.print(",");
}
}
System.out.print("]");
System.out.print(" -> converted: ");
System.out.println(Integer.valueOf(StringUtils.join(intArrs)));
}
}
Output
int arrays: [2,0,1,9] -> converted: 2019
The way 5
package com.jackrutorial;
import java.util.Arrays;
public class ArrayToIntegers5 {
public static void main(String[] args) {
int intArrs[] = { 2, 0, 1, 9 };
System.out.print("int arrays: [");
for (int i = 0; i < intArrs.length; i++) {
System.out.print(intArrs[i]);
if (i < intArrs.length - 1) {
System.out.print(",");
}
}
System.out.print("]");
System.out.print(" -> converted: ");
System.out.println(Arrays.toString(intArrs).replaceAll("\\D+",""));
}
}
Output
int arrays: [2,0,1,9] -> converted: 2019
