Double to string problem
i write such code
double a = 4.3
double b = 3
System.out.println(a*b)
why return value is 12.8999999999999
how to make it return right string?Please help me!
Computers can't accurately handle certain floatingpoint values, that's a fact.
Use the DecimalFormat class to format the string to having a certain amount of digits after the decimal point, that should give you the correct value (or at least a nicer looking one).
Similar Messages
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Double.parseDouble(String) - problems when string is in scientific notation
Hello guys,
I'm doing some numerical calculations and I wonder whether it is possible for Double.parseDouble(String) to parse string in the scientific notation i.e. 1.0824234234E-10. Is it the notation itself causing the exception : NumberFormatException or the number is just too big/small and double can't hold it ?
If it's just the notation how can I fix it ?
Regardsi'm not quite sure whether double odoes not allow it.
perhaps consider the api Double.valueOf() and the testing code provided; reproduced below:To avoid calling this method on a invalid string and having a NumberFormatException be thrown, the regular expression below can be used to screen the input string:
final String Digits = "(\\p{Digit}+)";
final String HexDigits = "(\\p{XDigit}+)";
// an exponent is 'e' or 'E' followed by an optionally
// signed decimal integer.
final String Exp = "[eE][+-]?"+Digits;
final String fpRegex =
("[\\x00-\\x20]*"+ // Optional leading "whitespace"
"[+-]?(" + // Optional sign character
"NaN|" + // "NaN" string
"Infinity|" + // "Infinity" string
// A decimal floating-point string representing a finite positive
// number without a leading sign has at most five basic pieces:
// Digits . Digits ExponentPart FloatTypeSuffix
// Since this method allows integer-only strings as input
// in addition to strings of floating-point literals, the
// two sub-patterns below are simplifications of the grammar
// productions from the Java Language Specification, 2nd
// edition, section 3.10.2.
// Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt
"((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+
// . Digits ExponentPart_opt FloatTypeSuffix_opt
"(\\.("+Digits+")("+Exp+")?)|"+
// Hexadecimal strings
"((" +
// 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt
"(0[xX]" + HexDigits + "(\\.)?)|" +
// 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt
"(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" +
")[pP][+-]?" + Digits + "))" +
"[fFdD]?))" +
"[\\x00-\\x20]*");// Optional trailing "whitespace"
if (Pattern.matches(fpRegex, myString))
Double.valueOf(myString); // Will not throw NumberFormatException
else {
// Perform suitable alternative action
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Double.html -
Double.parseDouble(String) : Problem to parse large String
Hello,
I need to convert A String to a Double in my application without rounding of digits.
I have used the Double.parseDouble(String) method.
The maximum string length can be 17 including dot(.)
So if my String is (of length 17)
Eg.
S= �9999999999.999999� then I am getting the double value as
d= 9999999999.999998(compare the last digit)
If s = �9999999999.111111� then d = 9999999999.111110
If s = �9999999999.555555� then d = 9999999999.555555 (result that I want)
If s = �9999999999.666666� then d = 9999999999.666666 (result that I want)
If s = �9999999999.777777� then d = 9999999999.777777 (result that I want)
If s = �9999999999.888888� then d = 9999999999.888887
If s = �9999999999.999999� then d = 9999999999.999998
If s = �9123456789.123456� then d = 9123456789.123456
But string length up to 16 is giving me the accurate result
So any body can explain me that why it is happening? And how can i get the accurate result.
Thanks in advanced.Hi,
Thank You for your suggestion. By which i can store
the big double number in Data base , but at some
point i require to parse a double value from a Double
reference.In that case if the Decimal value length
=> 16 then it the last digit changes or rounds.
coverting 9999999999.999999 Decimal value to double
value. It gives me 9999999999.999998 and
9999999999.9999999 gives me the 10000000000.0000000.
but the Double value 999999999.999999 is ok
and 999999999.99999999 rounds.Err, is there a follow up question in there? -
I'm having a problem in getting my double to convert to a string, here's my code so far.
public void calculatePayments()
double paymentAmount;
double monthlyInterestRate = (Double.parseDouble(interestBox.getText())/12)/100;
double amountOfLoan = Double.parseDouble(balanceBox.getText());
double numberOfPayments = Double.parseDouble(yearsBox.getText()) * 12;
paymentAmount = (amountOfLoan * monthlyInterestRate) / (1 - Math.pow(1/(1 + monthlyInterestRate),numberOfPayments));
Double.toString(paymentAmount);
tableBox.append(paymentAmount);
And here's the error message I get:
ProgramInterface.java:134: append(java.lang.String) in javax.swing.JTextArea cannot be applied to (double)
tableBox.append(paymentAmount);
As always, help is appreciated.This line returns a String but has no affect on paymentAmount.
Double.toString(paymentAmount);To covert the double to String you can save the return in a variable
String s = Double.toString(paymentAmount);
tableBox.append(s);or combine them
tableBox.append(Double.toString(paymentAmount)); -
Calculating double from String
Hello again
I just have a quick question here, that confused me a bit (though I guess it makes sense)
If I try to print the double 1 + 2 * 3, it will output 7.
But I have a JTextField with the string 1 + 2 * 3, and I try to parse it as a double, it won't let me.
Am I doing something since it doesn't work? To me it seems logic that it should be able to parse a string as a double, if it can calculate the double without a problem.
Do you have any ideas?
Any help here is appreciated
Thanks in advance
Ulverbeast
Edited by: Ulverbeast on Feb 25, 2010 1:07 PMUlverbeast wrote:
But in the second example it tries to parse the whole string as a double?As far as Java is concerned, a string is just a bunch of characters. Java doesn't know that this particular string happens to be a mathematical expression that could be evaluated.
If you want to evaluate a string as a mathematical expression you can do that out-of-the-box if you are using Java 6, through the new ScriptEngine functionality. Java 6 ships with a script engine that can evaluate JavaScript, so in this case you could do:
import javax.script.*;
public class EvalExample {
public static void main(String[] args) {
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine jsEngine = mgr.getEngineByName("JavaScript");
try {
Double result = (Double) jsEngine.eval("1 + 2 * 3");
System.out.println(result);
} catch (ScriptException ex) {
ex.printStackTrace();
}(Note that the cast to Double will fail if the expression you evaluate does not result in a number.)
Edited by: Torgil on Feb 25, 2010 8:12 PM: Figured I should make the example an SSCCE :) -
I am looking for a way to convert double to String.
I think that I have to use wrapper like Double class and use toString(double d), but I am not sure how to do it.
Since toString() is static method, I do not have to have an instance of the Double class, so I was wondering what's the correct way to do it.
I need something like this:
String MyString = new String (String1.concat ( My_doubleNumber.Double.toString() ) );
Any Suggestions?
Thanks!!!WOW thanks a lot. These are definately better than what I thought of doing originally.
In case I need to use the wrapper class somewhere else, I am just wondering what would be a proper use of Double and String? -
Converting Double to String without exponent
Hi all,
I am reading some values from Excelsheet using apache POI library. I have large numbers that need to stored into database as string and not numbers. hence, while reading the excelsheet values, i convert these number.. and the are received as double. While converting double into string I noticed that some values are represented in exponential form.. I would like to avoid this and have pure number values in the form of string,,..
Can anybody tell me how to do it?
Thanks in advance,
Abdel Olakarajava.text.DecimalFormat
-
Kinda urgent please help pass strings to doubles and strings to ints
Need to know how to pass strings to doubles and strings to ints
and to check if a string is null its just if (name == null;) which means black right?
like size as a string and then make the string size a doublecupofjava666 wrote:
Need to know how to pass strings to doubles and strings to ints
and to check if a string is null its just if (name == null;) which means black right?
like size as a string and then make the string size a doubleThink he means blank.
Check the Wrapper classes (Double, Integer) in the api.
parseInt() parseDouble() both take a string and return a primitive.
String s = null;
if(s == null) should do the trick!
Regards.
Edited by: Boeing-737 on May 29, 2008 11:08 AM -
Printing out double quote string
Hello,
I would like to know how can i print out the double quote string (")
in JSP using out.print(), because a double qoute has already used
for indicating the string. If the string that i want to print out is including double quote("), how can i print that string out.
THX !out.println("\"mystring\"");
generally: backslash "\" is used in Java to quote special characters e.g. out.println("c:\\my documents\\bla"); -
POI getCellStyle and empty string problem
I'm having a problem getting the style of a cell from and excel input file and setting to an output file.
I also have a problem recognizing blank cells that are not null in the input file here is my code any help would be great.
package Trace;
import java.io.*;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.hssf.util.HSSFColor;
import java.util.StringTokenizer;
import org.apache.poi.poifs.filesystem.*;
import java.lang.Runtime;
public class Converter1 {
private static short bhyvb= 0;
private static short foreground, background;
private static String[][] cellGridOut;
private static int numRows, numColumns, clock;
private static POIFSFileSystem fs;
private static HSSFWorkbook wbin, wbout;
private static HSSFSheet sheetIn, sheetOut;
private static HSSFRow rowIn, rowOut;
private static HSSFCell cellIn, cellIn1, cellOut;
private static FileOutputStream fileOut = null;
private static String rowIterator, rowIterator1;
private static HSSFCellStyle style, style1;
public static void main(String[] args) {
//Take in 2 inputs mandatory, Input Event Trace excel file and Time Interval respectively
if (args.length != 1)System.err.println("Input Excel File");
//Create a new POI file system and HSSF workbook with your excel input file
InputStream input = Converter.class.getResourceAsStream(args[0]);
try{
fs = new POIFSFileSystem(input);
wbin = new HSSFWorkbook(fs);
}catch (Exception e){System.err.println("File input error");}
wbout = new HSSFWorkbook();
sheetIn = wbin.getSheetAt(0);
numRows = sheetIn.getLastRowNum();//numRows=723
style = wbout.createCellStyle();
//style.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);
//style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
//get number of columns
rowIn = sheetIn.getRow(0);
boolean done = false;
int testNullPointer;
numColumns=0;
while(!done){
//System.out.println(ColumnInc);
cellIn = rowIn.getCell((short)numColumns);
numColumns+=1;
try{
testNullPointer = cellIn.getCellType();
}catch(NullPointerException npe){
done = true;
numColumns-=1; //number of columns = 25
converterIt();
//Create new output file, if it exists delete it
File myFile = new File("converted.xls");
if(myFile.exists()){
myFile.delete();
//Create new file output stream
try {
fileOut = new FileOutputStream(myFile);
} catch (IOException ioe) {}
//write all conversion data to output file
try{
wbout.write(fileOut);
fileOut.close();
}catch (IOException ioe) {}
public static void converterIt(){
boolean nextDone = false;
boolean nextDone1 = false;
for(int i=0; i<numColumns; i++){
clock =1;
rowIn = sheetIn.getRow(0);
cellIn = rowIn.getCell((short)i);
String getTopRow = cellIn.getStringCellValue();
sheetOut = wbout.createSheet(getTopRow+"_s"+i);
sheetOut.setColumnWidth((short)0, (short)(13 * 256));
sheetOut.setDefaultColumnWidth((short)25);
for(int j=0; j<=numRows; j++){
if(j==0){
rowIn = sheetIn.getRow(j);
cellIn = rowIn.getCell((short)i);
String temp2 = cellIn.getStringCellValue();
rowOut = sheetOut.createRow((short)j);
cellOut = rowOut.createCell((short)j);
cellOut.setCellValue(temp2);
cellOut = rowOut.createCell((short)(j+1));
cellOut.setCellValue("CLOCK");
if(j==1){
rowIn = sheetIn.getRow(j);
cellIn = rowIn.getCell((short)i);
double temp3 = cellIn.getNumericCellValue();
rowOut = sheetOut.createRow((short)j);
cellOut = rowOut.createCell((short)0);
cellOut.setCellValue(temp3);
cellOut = rowOut.createCell((short)1);
cellOut.setCellValue("");
nextDone=false;
nextDone1=false;
if(j>1){
rowIn = sheetIn.getRow(j);
try{
cellIn = rowIn.getCell((short)i);
}catch(NullPointerException npe){
rowIterator = "";
nextDone=true;
if(!nextDone){
try{
rowIterator = cellIn.getStringCellValue();
style = cellIn.getCellStyle();
}catch(NullPointerException npe){}
if(j==2){
rowOut = sheetOut.createRow((short)(clock+1));
cellOut = rowOut.createCell((short)0);
cellOut.setCellValue(rowIterator);
cellOut = rowOut.createCell((short)1);
cellOut.setCellValue(j-1);
clock+=1;
}else{
rowIn = sheetIn.getRow(j-1);
try{
cellIn = rowIn.getCell((short)i);
}catch(NullPointerException npe){
rowIterator1 = "";
nextDone1=true;
if(!nextDone){
try{
rowIterator1 = cellIn.getStringCellValue();
}catch(NullPointerException npe){}
if(rowIterator1!=rowIterator && j>2){
rowOut = sheetOut.createRow((short)clock+1);
cellOut = rowOut.createCell((short)0);
cellOut.setCellValue(rowIterator);
//System.out.println(style);
cellOut.setCellStyle(style);
cellOut = rowOut.createCell((short)1);
cellOut.setCellValue(j-1);
clock+=1;
}//if
}//for
}//for
}//converterIt
}//Converter1 CLASSENDI am not sure about the cell style as it looks like you are doing it right. For the null or blank cells it looks like you are only checking for null not "".
-
So I have this piece of code to save rows of data into a text file. The problem I'm having is that some times I am missing one of the data sets from the text file. It's always the same (first column) I say about .1% of the time.
Maybe it's just me but I really can't see why the first string would be missing. As far as I know the double going into Number to String can never be empty, right ? so the string shouldn't be empty either. I really don't see why or where the string goes missing. Maybe I'm not seeing something...
To clirify all the other data out of the concatenate string is there except the first string, where this string goes missing I really don't know. Any input is appreciated.
This is in LabVIEW 2010 by the way.
Here's how the data comes out on the file:So here's the queue, I had to make some changes to it so I could post it but nothing related to the file management.
Basically these are the commands I send to it during a test:
1) DCE.Initialize (only at application initialization)
2) DCE.Initialize.RawFile (this comes from a GUI queue)
3) DCE.Start.SaveData (from GUI queue)
4) DCE.Process.DataToFile (from a DAQ loop that is always running and passes the Raw Data cluster)
5) DCE.Stop.SaveData (from GUI queue)
6) DCE.Close.File (from GUI queue)
Notes:
- No other queues send messages to this queue other than the GUI and DAQ loop.
- I did monitor the queue and there is never a backup of unprocessed elements.
- Not sure if it matters but so far this has only happened when running as an executable.
- Like I mentioned before this only happens in about .1% of the data sets.
Thanks
Attachments:
Data Collection Queue.zip 87 KB -
Hi ,
I have one text file with delimiter as dollar symbol which is imported from one text file.
Now I try to upload the data from this text file into oracle table. Everything inserted properly but one field �Location� values not inserted properly.
The Original Data
1515$$HARRI SMITH$$23/08/2006$$ UNITED KINGDOM $$00:00:48$$23.40
1514$$John$$23/08/2006$$LONDON$$00:00:48$$ 23.40
The table shows like
code Name date Location Duration cost
1514 John 23/08/2006 LONDON 00:00:48 23.40
1515 HARRI SMITH 23/08/2006 UNITED KINGDOM 00:00:48
if the value of the "Location" is single word it comes properly.
The value of the "Name" come properly. even it has double value.
But Location only the problem when it is double value.
Please give me any one solution !
This is my part of the code :
BufferedReader inn = new BufferedReader(new FileReader("c:\\output.txt"));
while ((lines = inn.readLine()) != null) {
if (!(lines.equals(" "))){
if (!(lines.startsWith("--") || lines.trim().length() <=0 )){
if (!(lines.startsWith(" ") || lines.trim().length() <=0 )){
st = new StringTokenizer(lines, "$$");
code = st.nextToken();
name = st.nextToken();
date = st.nextToken();
location = st.nextToken();
duration = st.nextToken();
cost = st.nextToken();
pstmt = conn.prepareStatement ("insert into tele_report (code,name,r_date, ,location,duration,cost) values (?,?,?,?,?,?)");
pstmt.setString(1,code);
pstmt.setString(2,name);
pstmt.setString(3,date);
pstmt.setString(4,location);
pstmt.setString(5,duration);
pstmt.setString(6,cost);Please can anybody help me.. !
Thanks
Merlin RoshinaAssuming your variables are filled correctly
http://java.sun.com/j2se/1.5.0/docs/api/java/util/StringTokenizer.html#StringTokenizer(java.lang.String, java.lang.String)
why fill out 7 fields with 6 values?
insert into tele_report (code,name,r_date, ,location,duration,cost)
insert into tele_report (1,2,3, ,4 ,5,6,7)
values (?,?,?,?,?,?)
values (1,2,3,4,5,6)Do you see it?
maybe this will help
insert into tele_report (code,name,r_date,NULL ,location,duration,cost)
Or
insert into tele_report (code,name,r_date,DEFAULT ,location,duration,cost) -
Hi,
in my programe i have the following calculation
double a= 12;
double b= 74;
tonum = Math.pow(a,b);
charcount = new Double(count).toString();
System.out.println("The value of charcount is : "+ charcount);
when i do this it displays "7.234561410946297E79"
how do i display the number without this "E" ??
thanksThe problem is you cannot get 7*10^79 into a long.
I slammed out this code:
<code>
import java.text.NumberFormat;
public class Test {
public static void main( String[] arg ) {
double d = 7.234561410946297E79;
System.out.println( NumberFormat.getInstance().format( d ));
</code>
and got this output:
72,345,614,109,462,970,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000
Probably still not exactly what you are looking for, but take a look at the NumberFormat class and see if you think it will work for you.
} -
Hello All:
I need to write the following line into a file.
The line is: <?xml version="1.0" endcoding="UTF-8"?>
Below is the excerpt of my code:
BufferWriter bw = new BufferedWriter(new FileWriter("test.xml"));
String str = "<?xml version="1.0" endcoding="UTF-8"?>";
bw.write(str+System.getProperty("line.separator");
When I complie this Java code, I encountered the "; is expected" error because the compiler thought that the string ends at "<?xml version=".
Can anyone tell me how to solve this problem?
Thanks!Observe this:
String str = "<?xml version="1.0" endcoding="UTF-8"?>";
In this statement, the " is recognized as opening of string and closing of string. In this case, the string is ended like "<?xml version=", because its within the code. You might want to try something like:
String str = "<?xml version=\"1.0\" endcoding=\"UTF-8\"?>";
The \ character will make the subsequence characters in the string to be as a character in string, rather than a double quote to end the string until a " is met. -
SSRS Report Returning Double Quote string from a Single Quote String
Hi, I'm getting weird thing in resultset from SSRS report when executed. When I pass parameter to a report, which passes String that has single quote value to a split function , it returns rows with double quote.
For example following string:
'N gage, Wash 'n Curl,Murray's, Don't-B-Bald
Returns:
''N gage, Wash ''n Curl,Murray''s, Don''t-B-Bald
through SSRS report.
Here is the split function Im using in a report.
CREATE Function [dbo].[fnSplit] (
@List varchar(8000),
@Delimiter char(1)
Returns @Temp1 Table (
ItemId int Identity(1, 1) NOT NULL PRIMARY KEY ,
Item varchar(8000) NULL
As
Begin
Declare @item varchar(4000),
@iPos int
Set @Delimiter = ISNULL(@Delimiter, ';' )
Set @List = RTrim(LTrim(@List))
-- check for final delimiter
If Right( @List, 1 ) <> @Delimiter -- append final delimiter
Select @List = @List + @Delimiter -- get position of first element
Select @iPos = Charindex( @Delimiter, @List, 1 )
While @iPos > 0
Begin
-- get item
Select @item = LTrim( RTrim( Substring( @List, 1, @iPos -1 ) ) )
If @@ERROR <> 0 Break -- remove item form list
Select @List = Substring( @List, @iPos + 1, Len(@List) - @iPos + 1 )
If @@ERROR <> 0 Break -- insert item
Insert @Temp1 Values( @item ) If @@ERROR <> 0 Break
-- get position pf next item
Select @iPos = Charindex( @Delimiter, @List, 1 )
If @@ERROR <> 0 Break
End
Return
End
FYI: I'm getting @List value from a table and passing it as a string to split function.
Any help would be appreciated!
ZKAnother user from TSQL forum posted this code which is returning the same resultset but when I execute both codes in SQL server it works and return single quote as expected.
https://social.msdn.microsoft.com/Forums/sqlserver/en-US/8d5c96f5-c498-4f43-b2fb-284b0e83b205/passing-string-which-has-single-quote-rowvalue-to-a-function-returns-double-quoate?forum=transactsql
CREATE FUNCTION dbo.splitter(@string VARCHAR(MAX), @delim CHAR(1))
RETURNS @result TABLE (id INT IDENTITY, value VARCHAR(MAX))
AS
BEGIN
WHILE CHARINDEX(@delim,@string) > 0
BEGIN
INSERT INTO @result (value) VALUES (LEFT(@string,CHARINDEX(@delim,@string)-1))
SET @string = RIGHT(@string,LEN(@string)-CHARINDEX(@delim,@string))
END
INSERT INTO @result (value) VALUES (@string)
RETURN
END
GO
ZK
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