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String decimal to percentage in java [duplicate]

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java how to make user friendly percentage output from float number
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I have a string value as below:
String percValue = "0.0209"
How can I convert this to something like as below
String formatedValue = "2.09%";
Can someone help me what is the simple and best way to convert this?

One good way would be to:
convert your percentage string to a number (needs to be a double type variable, so it can hold the decimal places...),
multiply the value by 100 to make it a percentage,
re-format the number in a string.
String percValue = "0.0209";
double percentage = Double.parseDouble(percValue) * 100;
String formattedValue = String.format("%.2f%%", percentage);
Explanation:
Double.parseDouble() takes your string as a parameter and returns a double value which you can do things like multiplication and addition with, and
String.format() lets you precisely control how your number is converted back to a String!
"%.2f" means "Take the next argument which is a floating-point variable and put it here, with two decimal places".
"%%" means "print a single '%'". You need two to "escape" it, since percent symbols are not literally interpreted in format strings.

You should parse the String into a double, multiply by 100, and then append the % sign to it as follows:
String percValue = "0.0209";
double per = Double.parseDouble(percValue);
String percentage = (per*100)+"%";

You need to parse your string value and then multiply by 100, something like this:
String percValue = "0.0209";
double value = ( Double.parseDouble(percValue)) * 100;
String formatedValue = value + "%";

Convert String to BigDecimal(for Big numbers) and multiply by 100.
String percValue = "0.0209";
BigDecimal temp=new BigDecimal(percValue).multiply(BigDecimal.valueOf(100)).stripTrailingZeros();
String formatedValue =temp.toString() + "%";

Java Object format to String Number with Decimals

so I have an array list of Objects and in it are string numbers. I want to add decimal places to these numbers (8).
String value = String.valueOf(accountEntry.get(4));
double amount = Double.valueOf(value);
String formatted = String.format(Locale.GERMANY,"%.8f",amount);
accountEntry.add(formatted);
For example 101700000000 should output 1017 but instead it is 101700000000,00000000
Does anyone know where the problem is?

Hello try something like this using Regex , this way you can remove all zeros at the end.
String value = String.valueOf("101700000000");
double amount = Double.valueOf(value);
String formatted = String.format(Locale.GERMANY,"%d",(long)amount);
formatted = formatted.replaceAll("0+$", "");
System.out.println(formatted);
Input :101700000000 ===> Output: 1017

Does anyone know where the problem is?
Your Input is : 101700000000 and you are formatting String.format(Locale.GERMANY,"%.8f",amount); In here your output will be 101700000000,00000000 So for understand this String Format will not transform your input magicaly to 1017. You need to use another algorithm for this problem

Java: convert string to double\long, divide by 100 and convert it back to string (SpEL)

This is what I have:
A string var amount with value: "123.45".
What I need is to divide it by 100 on a SpEL expression. So I went like this:
T(java.lang.Double).valueOf(amount) / 100D
And then, return the result as a string again.
How can I achieve it? I tried
T(java.lang.Double).toString(T(java.lang.Double).valueOf(amount) / 100D)
but is not working. And instead of dividing is multipling for some reason :-\
Thanks in advance

Consider, You have a variable named amount
String amount = "123.45";
//The following code converts 123.45 into Double and divides it by 100
Double dividedValue = new Double(Double.valueOf(amount)/100);
//To convert the resultant double value into String
String resultantValue = dividedValue.toString();
Hope, it will help you :)

Try converting the adjusted double to a string using String#valueOf:
T(java.lang.String).valueOf(T(java.lang.Double).valueOf(amount) / 100)

Here is a full explanation about convertion in double and back to String.
A possibility is
double myValue = 88.22;
String doubled = String.valueOf(myValue);
And the toString() method is a possibility to transfer it back.

How to convert a string with multiple points to double in android

I have a string "3,350,800" with multiple points I want to convert to double but have error multiple points
String number = "3,350,800"
number = number.replace(",", ".");
double value = Double.parseDouble(number);
Error : java.lang.NumberFormatException: multiple points

The . character is used as a decimal point in English, and you cannot have more than one of those in a number.
It seems like you're using it as a thousands separator though. This is legal in several locales - you just need to use one that allows it, e.g.:
String number = "3.350.800";
NumberFormat format = NumberFormat.getInstance(Locale.GERMAN);
double value = format.parse(number).doubleValue();

Mix of other answers, no reason to change the , for . and then fetch the German local.
String number = "3,350,800";
NumberFormat format = NumberFormat.getInstance();
double value = format.parse(number).doubleValue();
System.out.println(value);
Output:
3350800.0

you need to use something like this :
String number = "3,350,800";
number = number.replaceAll(",", "");
double value = Double.parseDouble(number);
System.out.println(value);

What number are you trying to get?
3.350.800 is what you're trying to parse as a double,
but that's obviously not a number, since there are "multiple points".
If you just wanna get 3,350,800 as your number, simply change this line -
number = number.replace(",", ".");
to this -
number = number.replace(",", "");

How to check if a string variable contains negative value or not in java

I need to put a constraint for negative values on string variable. For Eg :--
string zeroval = "0.0000"
String x = "";
if (x==null) || (x.equals(zeroval)) { // code which checks if string x has 0 or null value
x = "--" // replace it by --
}
similarly i want to add another piece of code which checks if String x contains any negative values (for eg : "-0.025") and replace it by --
The above String x should not contain null/zero/negative values
Please help
Note :- In order to add negative value check convert the string to float as i cannot use pattern matching technique for eg:- x.equals("-")

Is your input data always meant to contain valid numbers? If so, you could just use:
BigDecimal number = new BigDecimal(text);
if (number.compareTo(BigDecimal.ZERO) <= 0) {
text = "--";
}
This will validate that it really is a number as well as performing the check. Additionally:
It copes with other representations of 0, e.g. "0.00", "0", "+0"
It uses BigDecimal to avoid oddities in binary floating point representations (e.g. a very small positive value being seen as 0). Unlikely to be a problem, but fundamentally you've got decimal data, so you might as well parse it that way.

Convert it to Integer or double using wrapper class.
String number="12.3434"
if(Double.parseDouble(number)<0)
//do stuff here

You could check if the string starts with a "-":
if (x==null) || (x.equals(zeroval) || x.startsWith("-")) {
x = "--";
}
I can't help but feel you are doing something ill-advised by using Strings to represent numerical data.

You could use Double.parseDouble(String) or Float.parseFloat (String). These methods will help you get a double or a float, respectively.
After this, you can easily check if the value is negative.