Represent double as integer without regex

Question

I am developing a calculator for android. Having a double field called result, which I then put into a TextView.

If say result = 20.0 then I must represent it as 20 (without point and a zero). If result = 20.0001 it should be displayed unchanged.

Now I do it with regular expressions but I guess it's not a good idea. Is there another way to represent double without a point and a zero if double actually is an integer (without digits after the point)?

score 1 · Answer 1 · answered Mar 17 '15 at 19:54

1

I hope I could understand your question. Maybe this will help you to solve your problem.

    double d = 20.0001;
    if ((int) d == d)
        System.out.println((int) d);
    else
        System.out.println(d);

answered Mar 17 '15 at 19:54

Marvin

55
11

Neeraj Jain · Answer 2 · 2015-03-17T20:21:43.980

1

How about Explicit type casting

double y=anyValue;
int x = (int) y;
if(x==y)
log.debug(x);
else
log.debug(y);

for Input y=3.00 the output will be 3 and for Input y=3.0001 the output will be 3.0001

edited Mar 17 '15 at 20:21

answered Mar 17 '15 at 19:55

Neeraj Jain

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adrCoder · Accepted Answer · 2015-03-17T20:01:36.877

0

Use (d % 1 == 0) { to check if your double does not have a decimal part, then use the intValue() method to get the integer out of the Double!

class testDouble {
public static void main(String[] args) {
    Double result = 20.001;
if (result % 1 == 0) {
    System.out.println(result + " Can be turned into integer, has no decimal part");
}
else {
    System.out.println(result + " Can not be turned into integer, has decimal part");
}
    result = 20.000;
if (result % 1 == 0) {
    System.out.println(result + " Can be turned into integer, has no decimal part");
    int intOfDouble = result.intValue();
    System.out.println(result + " Can be turned into integer " + intOfDouble);
}
}
}

OUTPUT :

20.001 Can not be turned into integer, has decimal part
20.0 Can be turned into integer, has no decimal part
20.0 Can be turned into integer 20

edited Mar 17 '15 at 20:01

answered Mar 17 '15 at 19:55

adrCoder

3,145
4
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Thank you for a quick and exect answer – Mar 17 '15 at 20:02
Glad that I could help and that it works! Please accept my answer as described here : http://meta.stackexchange.com/questions/5234/how-does-accepting-an-answer-work ! Thanks ! – adrCoder Mar 17 '15 at 20:02
Objection, your honor! OP said he has a `double` `result` not a `Double.` See [my answer](http://stackoverflow.com/a/29109020/1744774) for a one-liner; – Gerold Broser Mar 17 '15 at 20:34

score 0 · Answer 4 · answered Mar 17 '15 at 19:57

0

You could output the result as a formatted string:

public static String fmt(double d)
{
    if(d == (long) d)
        return String.format("%d",(long)d);
    else
        return String.format("%s",d);
}

answered Mar 17 '15 at 19:57

DigitalNinja

1,078
9
17

score 0 · Answer 5 · edited Mar 17 '15 at 20:33

0

Use the modulus % operator. Let us say your calculated value is:

double result;

if (x % 1) == 0   
    then you must have a whole number
    and you can use (int) result to cast it and int value
else //your number is not a whole number
    you will just use the result as is

edited Mar 17 '15 at 20:33

axblount

2,639
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answered Mar 17 '15 at 20:03

brosenlof

1
1

Gerold Broser · Answer 6 · 2015-03-17T20:48:31.807

Check your double result against a cast (long) result and create a string to be displayed accordingly with a one-liner:

double r;
String s;
for (int i = 2; i <= 3; i++) {
    r = 100d / i;
    // this is the essential line, all others are just testing noise
    s = r > (long) r ? String.valueOf(r) : String.valueOf((long) r);
    // ------------------------------------------------------------- 
    System.out.println(s);
}

Prints:

50
33.333333333333336

score -1 · Answer 7 · edited May 23 '17 at 11:45

-1

You could use modulus division like:

if((**doublevariablehere** % 1) == 0)
{
}

Code taken from here

edited May 23 '17 at 11:45

Community

1
1

answered Mar 17 '15 at 19:54

brso05

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Represent double as integer without regex

7 Answers7