Integer.parseInt() method
Hi to all
I'm trying to write a piece of a lexical analizer in Java and I need the method the does the contrary of Integer.parseInt() method in order to do the following:
once i have as input an integer and with the Integer.parseInt() method i know it's value I want to count it's digits. I'm sure there is a method that do the contrary of Integer.parseInt() method that I can't remeber.
Thanks for your help
Maddy
Integer.parseInt() takes in a String and returns an int value, so the contrary would take in an int value and return a String. Is this what you want?
You can use Integer.toString()
Also, when you call Integer.parseInt(String s), you should already have the number as a String (the argument).
Maybe I am not understanding the question right. If not, please explain exactly what you need.
Similar Messages
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NetBeans 6.5 - Integer.parseInt(String)
Hello,
I'm beginner with NetBeans 6.5.
I created a simple hello-java application and a simple hello java-web JSF application.
I have no error with hello-java application for these 2 lines:
String name = "12345";
int aInt = Interger.parseInt(name) ;
but I get exception handler from java-web JSF application as below.
Hope you help me to solve this, Thanks !
Exception Handler
Description: An unhandled exception occurred during the execution of the web application. Please review the following stack trace for more information regarding the error.
Exception Details: java.lang.NumberFormatException
null
Possible Source of Error:
Class Name: java.lang.Integer
File Name: Integer.java
Method Name: parseInt
Line Number: 415
Source not available. Information regarding the location of the exception can be identified using the exception stack trace below.
......they're different, i was trying to convert the string entered in a TextField to a number, and thought that I already hard coded '12345' in the code to see whether the parseInt works therefore i didn't enter anything in the TextField.
thanks raychen ! -
Integer.parseInt problems
Hi everyone,
I want to use the Integer.parseInt and Byte.parseByte methods to parse hex strings - the problem is that they don't parse negative 2's complement numbers, they explicitly need a minus sign in front of an otherwise unsigned number to show that it's negative.
Examples:
//System.out.println(Integer.parseInt(Integer.toHexString(-1), 16)); //NumberFormatException
System.out.println(0xffffffff); // but this prints -1
//System.out.println(Byte.parseByte("ff", 16)); //NumberFormatException
System.out.println(Byte.parseByte("-1", 16)); // but this worksIs there some other method that will do what I need?
Regards,
JonathanHere's a dirty solution:public class Test {
private static char[] digits = new char[] {
'0', '1', '2', '3',
'4', '5', '6', '7',
'8', '9', 'a', 'b',
'c', 'd', 'e', 'f'
public static void main (String[] parameters) {
String number = Integer.toHexString (parameters[0].equals ("+") ? Integer.MAX_VALUE : parameters[0].equals ("-") ? Integer.MIN_VALUE : Integer.parseInt (parameters[0]));
if ((number.length () == 8) && (getPosition (number.charAt (0)) >= 8)) {
String newNumber = "";
for (int i = 0; i < number.length (); i ++) {
newNumber += digits[15 - getPosition (number.charAt (i))];
number = "";
boolean carry = true;
for (int i = 7; i >= 0; i --) {
int position = getPosition (newNumber.charAt (i));
if (carry) {
position = (position + 1) % 16;
carry = (position == 0);
number = digits[position] + number;
number = "-" + number;
int numberAsInt;
try {
numberAsInt = Integer.parseInt (number, 16);
} catch (NumberFormatException exception) {
// -8000000
numberAsInt = Integer.MIN_VALUE;
System.out.println (numberAsInt);
private static int getPosition (char digit) {
int position = 0;
while ((position < digits.length) && (digits[position] != digit)) {
position ++;
return position;
}Start with java Test <yourNumber>: + for Integer.MAX_VALUE, - for Integer.MIN_VALUE.
I don't claim it's good or efficient: it's working though. There's lots of things to improve.
Kind regards,
Levi -
Something's wrong with my Integer.parseInt...
hi...I think something's wrong with my code.
when i don't add the loop for(int s = h; s > 0; s--) { }, it's correct, but when i do, it shows:
java.lang.NumberFormatException: 27.0
at java.lang.Integer.parseInt(Integer.java:414)
at java.lang.Integer.parseInt(Integer.java:454)
at chiayaochien3.evaluate.find(evaluate.java:55)
at chiayaochien3.evaluate.operate(evaluate.java:48)
at chiayaochien3.Main.main(Main.java:10)
Exception in thread "main"
(But i am sure the things in Integer.parseInt is String...)
public class Main
public static void main(String[] args)
String[] data = {"3","+","12","*","27","/","1","-","6", "+", "222"};
String[] operStack = null;
String[] numStack = null;
myStack num1 = new myStack();
myStack num2 = new myStack();
myStack oper1 = new myStack();
myStack oper2 = new myStack();
int calculateNum1 = 0;
int calculateNum2 = 0;
String calculate1 = null;
String calculate2= null;
String oper = null;
double resultNum = 0;
double result = 0;
int operSize = 0;
int numSize = 0;
int h = 0;
for(int i = 0; i < data.length; i++) {
String f = data;
if(f.compareTo("+") == 0)
oper1.push(f);
else if(f.compareTo("-") == 0)
oper1.push(f);
else if(f.compareTo("*") == 0) {
oper1.push(f);
h++;
else if(f.compareTo("/") == 0){
oper1.push(f);
h++;
else if(f.compareTo("^") == 0){
oper1.push(f);
h++;
else
num1.push(f);
}//end of for
for(int s = h; s > 0; s--){
while(!oper1.isEmpty()) {
calculateNum1 = Integer.parseInt((String)num1.pop());
oper = (String)oper1.pop();
if(oper.compareTo("*") == 0) {
calculateNum2 = Integer.parseInt((String)num1.pop());
resultNum = calculateNum2*calculateNum1;
num2.push(String.valueOf(resultNum));
while(oper1.isEmpty() == false && num1.isEmpty() == false) {
oper2.push((String)oper1.pop());
num2.push((String)num1.pop());
}//end of while
}//end of if
else if(oper.compareTo("/") == 0) {
calculateNum2 = Integer.parseInt((String)num1.pop());
resultNum = calculateNum2/calculateNum1;
num2.push(String.valueOf(resultNum));
while(oper1.isEmpty() == false && num1.isEmpty() == false) {
oper2.push((String)oper1.pop());
num2.push((String)num1.pop());
}//end of while
}//end of else-if
else if(oper.compareTo("^") == 0) {
calculateNum2 = Integer.parseInt((String)num1.pop());
resultNum = Math.pow(calculateNum2, calculateNum1);
num2.push(String.valueOf(resultNum));
while(oper1.isEmpty() == false && num1.isEmpty() == false) {
oper2.push((String)oper1.pop());
num2.push((String)num1.pop());
}//end of while
}//end of else-if
else {
num2.push(String.valueOf(calculateNum1));
oper2.push(oper);
}//end of else
}//end of while
while(!oper2.isEmpty()){
oper1.push((String)oper2.pop());
while(!num2.isEmpty()) {
num1.push((String)num2.pop());
while(!num1.isEmpty()) {
System.out.println(num1.pop());
while(!oper1.isEmpty())
System.out.println(oper1.pop());
}//end of main
}//end of class"27.0" is not an integer. (Well, it is numerically, but it's a representation of a double.)
-
Integer.parseInt() error
I am writing an applet that reads a file containing groups of 5 lines of which the first 4 hold a number. Then these values are used to draw circles. When I compile, I get this error message: "incompatible types
found: int, required: java.lang.Integer, ia = Integer.parseInt(a)".
Suggestions?
Thanks!
import java.awt.*;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
import java.awt.geom.*;
public class Section2 extends Applet {
TextField tekst;
public void init() {
resize(400,400);
tekst = new TextField(20);
add(tekst);
public void paint(Graphics g) {
try {
String a, b, c, d, e;
Integer ia, ib, ic, id;
File inputFile = new File(tekst.getText());
FileReader in = new FileReader(inputFile);
BufferedReader BR = new BufferedReader(in);
while (e != null){
a = BR.readLine();
b = BR.readLine();
c = BR.readLine();
d = BR.readLine();
e = BR.readLine();
ia = Integer.parseInt(a);
ib = Integer.parseInt(b);
ic = Integer.parseInt(c);
id = Integer.parseInt(d);
Graphics2D g2d = (Graphics2D)g;
Ellipse2D.Double circle = new Ellipse2D.Double(ia, ib, ic, id);
g2d.setPaint(Color.blue);
g2d.draw(circle);
in.close();
catch (IOException e) {}Ok everything works! I still have some questions:
*** Can anyone tell me why I get this:
--------------------Configuration: Section2 - j2sdk1.4.0_01 <Default>--------------------
Note: C:\Program Files\Xinox Software\JCreator LE\MyProjects\Section textfield\Section2.java uses or overrides a deprecated API.
Note: Recompile with -deprecation for details.
Process completed.
*** Is there a way to go from string to double in one step?
This is the code:
import java.awt.*;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
import java.awt.geom.*;
public class Section2 extends Applet {
TextField tekst;
Button knop;
public void init() {
resize(400,400);
tekst = new TextField(20);
add(tekst);
knop = new Button("teken");
add(knop);
public boolean action (Event e, Object o){
if(e.target.equals(knop)){
repaint();
return true;
public void paint(Graphics g) {
try {
String a, b, c, d, e;
Integer ia, ib, ic, id;
File inputFile = new File(tekst.getText());
FileReader in = new FileReader(inputFile);
BufferedReader BR = new BufferedReader(in);
e = "start";
if (tekst.getText() != null){
while (e != null){
a = BR.readLine();
b = BR.readLine();
c = BR.readLine();
d = BR.readLine();
e = BR.readLine();
ia = Integer.valueOf(a);
ib = Integer.valueOf(b);
ic = Integer.valueOf(c);
id = Integer.valueOf(d);
Graphics2D g2d = (Graphics2D)g;
Ellipse2D.Double circle = new Ellipse2D.Double(ia.doubleValue(), ib.doubleValue(), ic.doubleValue(), id.doubleValue());
g2d.setPaint(Color.blue);
g2d.draw(circle);
in.close();
catch (IOException e) {} -
Integer.parseInt, NumberFormatException
Hi,
I'm trying to convert numbers back and forth with parseInt and toHexString.
The number that I want to manipulate is 56789abc.
String str = Integer.toHexString(1450744508);
int i = 0;
try
i = Integer.parseInt(str, 16);
catch(NumberFormatException e)
e.printStackInfo();
I'm not sure why I'm getting NumberFormatException, since I think
56789ABC doesn't cross the line. It's not out of boundary.
Any suggestion or help really be appreciated.
Thanks in advance,I don't know what you're talking about.
Integer.parseInt("56789ABC", 16);gives 1450744508
Works fine. -
String equivalent of Integer.parseInt()
Hey..
Integer.parseInt() reads an integer that is being inputted right? what im looking though is some sort of a String equivalent of Integer.parseInt.
ex:
nString = JOptionPane.showInputDialog("Enter number:");
n = Integer.parseInt(nString);
what im looking:
nString = JOptionPane.showInputDialog("Enter text:");
n = ? (nString);
a keyword that reads the text inputted.how do i reset the counter to 0 if the user tries again? because it doesn't reset and it makes a logical error if the user tries again.
while (trya != 0){
if ((trya > 1) || (trya < 0))
break;
else{
z=JOptionPane.showInputDialog("Choose Difficulty:\n[1]BATHROOM SINGER\n[2]MAINSTREAM MUSICIAN\n[3]GRAMMY WINNER");
x=Integer.parseInt(z);
switch(x){
case 1:
JOptionPane.showMessageDialog(null,"DIFFICULTY: BATHROOM SINGER");
String stringInput = JOptionPane.showInputDialog(q1);
if (stringInput.equals(a1)){
JOptionPane.showMessageDialog(null, "Correct!");
i++;
} else {
j++;
JOptionPane.showMessageDialog(null,"Wrong");
String stringInput29 = JOptionPane.showInputDialog(q15);
if (stringInput29.equals(a15)){
JOptionPane.showMessageDialog(null, "Correct!");
i++;
} else {
j++;
JOptionPane.showMessageDialog(null,"Wrong");
JOptionPane.showMessageDialog(null,"Correct answers: "+i+"\nWrong answers: "+j+"\nTHANKS FOR PLAYING");
break;
default:
JOptionPane.showMessageDialog(null,"Press either [1] [2] or [3]", "ERROR",JOptionPane.WARNING_MESSAGE);
break;
stry = JOptionPane.showInputDialog("Do you want to PLAY AGAIN? \n Press [1] for YES \n Press [0] for NO");
trya = Integer.parseInt(stry);
} -
Hi,
There is a new feature added in java 7 on integer, called as underscore '_" and it is working fine
if it is a normal int variable but if it is coming with String jvm throw the error.
if any one of you have java8 installed on your PC can you check this is working on that version.
int a = 1000_000;
String strNum = "1000_000";
// System.out.println("..abc..."+ Integer.parseInt(strNum));
System.out.println("a..."+a);
Thank you,
Shailesh.what is your actual question here?
bye
TPD -
hi
i hava a Doubt
i Confused the parseInt method. That is , while i am using
parseInt("Kona", 10)
it gives NumberFormatException
then i give
parseInt("Kona", 27) it gives 411787
i need some Clarification about this.
thanks.hi
i hava a Doubt
i Confused the parseInt method. That is , while i am
using
parseInt("Kona", 10)
t gives NumberFormatExceptionBase 10 parsing so only digits 0-9 inclusive are allowed.
>
then i give
parseInt("Kona", 27) it gives 411787 Base 27 parsing so digits 0-9 plus a-q and A-Q are allowed. These alpha values are treated as values (alpha-'a' + 10) and (alpha-'A' + 10) . -
Integer.parseInt()
Hi!
I have a problem that for an experienced programmer like you should be easy.
I have in my program:
int num = Integer.parseInt(numbers);
And I get:
Exception in thread "main" java.lang.NumberFormatException: For input string: "195400011111111111111113"
It (195400011111111111111113) looks like not an integer,and I tried:
long num = Integer.parseInt(numbers);
But I get the same error.
What could I do?
Thank you,
NataThat number is too big for an int, so Integer.parseInt doesn't like it. It doesn't matter if you put a long on the left side of the equals sign, Integer.parseInt only handles ints.
Do you know about the Long class? Have you looked at its docs to see if it might have something that can help you? -
Integer.parseInt(in.readLine()) - "null"
I just realized that if I don't enter a value in the following:
System.out.print("Enter the column you'd like to mark in: ");
int col = Integer.parseInt(in.readLine());I get this error:
Enter the column you'd like to mark in:
java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
at java.lang.Integer.parseInt(Integer.java:447)
at java.lang.Integer.parseInt(Integer.java:476)
at la5.TicTacToeDriver.main(TicTacToeDriver.java:37)
Exception in thread "main" Is there a way to prevent this error and prompt the user for a proper input (any integer will work).Enclose the parse attempt in a try/catch block.
-
Class of Integer.parseInt
Hi..,
I really need help. I am trying to make a really simple program. And that I want to make an argument class so that I can reuse it again and again without typing the long word (Integer...)
Here is the problem:
Rational r2 = new Rational(toInt(args[0]));
I think I should make a toInt method, but I don't know how. It is quite confusing. I think this toInt method, we should put it inside the main method. But i don't know yet.
Please Help me!well with the way you wrote it, toInt is a class, not a method. What you are probably envisioning is a class with a constructor which takes a String parameter and returns an int. Unfortunately, constructors don't return values. You can try using the object wrapper class Integer though.
One suggestion, if you hate the typing for getting arg parameters, make a method which takes the whole args array and parses them into a nice int array or some other data structure you dream up to make it easier? -
Error in Integer conversion method equals(...)???
Example:
Integer I = new Integer(0);
If (i.equals(0))
�.
As far as I know, equals(Object obj)�. Therefore, i.equals(0) should generate a compilation error. However, I teststed this with JCreator with the latest 1.6.0_03 jdk. It accepts it and treat the �0� as the actual value.
Therefore, if I do:
Integer I = new Integer(0);
If (i.equals(0))
�.
i.equals(0) return true. Shouldn't it be invalid instead? If returning true is correct, your documentation should reflect so. http://java.sun.com/docs/books/tutorial/java/data/numberclasses.html.
Input is greatly appreciated.That's due to autoboxing. See http://java.sun.com/j2se/1.5.0/docs/guide/language/autoboxing.html
If you want to see something really screwy, what do you think this returns?
Object o = true ? new Integer(1) : new Double(2.0); -
Is there any way to use Integer.parseInt using jstl
Hi
actually i m getting a string in a varible i need to convert it to int so that i can use it for further calculation.
so plz tell how to do that...
thanksThe exception clearly states the variable isn't a valid number. Print out the value and see what it is.
And no, you can't set the 'JSTL variable' for the simple reason that there are no 'JSTL variables' ( at least none that are public ). You're probably thinking of the EL. And no, you can't do anything there either.
People on the forum help others voluntarily, it's not their job.
Help them help you.
Learn how to ask questions first: http://faq.javaranch.com/java/HowToAskQuestionsOnJavaRanch
(Yes I know it's on JavaRanch but I think it applies everywhere)
---------------------------------------------------------------- -
Hello,
In my application I have a form field which a non-negative number should be entered in.
In order to make my application maximally user-friendly, I validate that field if it has a value entered, if the value entered is a number and if the number entered is negative.
I validate the string with a Integer.parseInt() method. If it throws a NumberFormatException, then the input string is not a number (empty or text) and I display a message "The input string is not a number...". When it doesn't throw anything, then I validate the number to negativity.
But when I enter string "5000000000" (five billions), the result is NumberFormatException and the resulting message is "The input string is not a number...", which is obviously bad. Is there a way to know whether the NumberFormatException was thrown because of invalid string or because of too large number was entered?
Moreover, if value -5000000000 (minus five billions) was entered, I would like to display message "Input number must be non-negative...", instead of "Number too big...".
Thanks
Edited by: Shagrat on Feb 19, 2009 2:20 AMShagrat wrote:
Thanks for a quick response.
I appreciate your suggestions, but using BigInteger would only move the size a little big futherWell, quite a lot further, to be honest. I'm currently running this code:
String x = "1";
while(true) {
BigInteger b = new BigInteger(x);
System.err.println(x.length());
x = x.concat("0");
}And it hasn't died yet, after several minutes, by which point the numbers are massive. Like, 10^10000 and counting. I wonder what on Earth your users will be doing that requires bigger numbers than that.
Sounds like you want to do some input validation before you even decide if you've got a number or not
Maybe you are looking for
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