[android-beginners] Re: separating the decimal from the whole?
Thanks for the answers, they were axactly what I was looking for - not
the math itself but how to do the math in Java language.
Thanks again, much appreciated I should make some headwind now.
On Mar 24, 8:38 am, sm1 wrote:
> here's a slower but sometimes more precise way, e.g., if you're
> dealing with currency:
>
> double d = 124.50d;
> BigDecimal ii = new BigDecimal(""+d);
> Log.d("whole and decimal","BigDecimal ii = "+ii+" = new BigDecimal
> (\"\"+d); d = "+d);
> Log.d("whole and decimal","whole = ii.intValue() = "+ii.intValue
> ());
> Log.d("whole and decimal","decimal = ii.remainder(BigDecimal.ONE)
> = "+ii.remainder(BigDecimal.ONE));
>
> extracts from the log:
>
> BigDecimal ii = 124.5 = new BigDecimal(""+d); d = 124.5
> whole = ii.intValue() = 124
> decimal = ii.remainder(BigDecimal.ONE) = 0.5
>
> sm1
>
> On Mar 23, 3:28 pm, droozen wrote:
>
> > I'm a bit confused about your question. You ask a question and then
> > pretty much answer it. :) There's other ways, as you say, but that's
> > pretty much how you do it in java, too.
>
> > x = 124.5
> > y = x - int(x) (so now y = 0.5 and x = 124.5)
> > z = x - y (so z = 124.0
>
> > a = y * 3 ( a now = 1.5 )
> > b = z + a ( here's you're only error. 124 + 1.5 will give you b =
> > 125.5, unless you are casting it to an int)
>
> > Some other ways.
>
> > String myX = Double.toString(x); (gives you x as a string)
> > String s = myX.substring(myX.indexOf(".") + 1) (s = everything after
> > the .)
> > String r = myX.substring(0, myX.indexOf(".") (r = everything before
> > the .)
>
> > a = Double.parseDouble(s) * 3 (Turn everything after the . back into a
> > double and multiply)
> > b = Double.parseDouble(r) + a (And turn everything before the . back
> > into a number and finish your calc
>
> > Of course, using string manipulation like this you'll have to have a
> > lot more checks for nulls and whatnot (what if there is no decimal
> > part, converting it to a string might not yield a . in the string).
>
> > Best way is as you posted, though.
>
> > On Mar 20, 10:36 pm, Jintsubo wrote:
>
> > > So I having a good crack at my first Android app, I've completed all
> > > the tutorials and suddenly realised I haven't a clue about how to do
> > > simple mathematics in Java. I have some (self taught) experience in
> > > PHP, Python etc, I'm no expert but I have managed to get the things
> > > done that I want to do.
>
> > > What I can do in Python but can't for the life of me figure out in
> > > javndroid; how to separate the decimal from the whole.
>
> > > for example, 124.50. I want to do some calcs using only the 0.50 and
> > > then when I'm finished, add it back onto the 124.0.
>
> > > x = 124.50
> > > y = x - int(x) (there are other ways but for simplicity sake)... y =
> > > 0.50
> > > z = x - y = 124.0
>
> > > a = y * 3 = 1.5
> > > b = z + a = 125.0
>
> > > Any pointers greatly appreciated.
>
> > > JR
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[android-beginners] Re: separating the decimal from the whole?
here's a slower but sometimes more precise way, e.g., if you're
dealing with currency:
double d = 124.50d;
BigDecimal ii = new BigDecimal(""+d);
Log.d("whole and decimal","BigDecimal ii = "+ii+" = new BigDecimal
(\"\"+d); d = "+d);
Log.d("whole and decimal","whole = ii.intValue() = "+ii.intValue
());
Log.d("whole and decimal","decimal = ii.remainder(BigDecimal.ONE)
= "+ii.remainder(BigDecimal.ONE));
extracts from the log:
BigDecimal ii = 124.5 = new BigDecimal(""+d); d = 124.5
whole = ii.intValue() = 124
decimal = ii.remainder(BigDecimal.ONE) = 0.5
sm1
On Mar 23, 3:28 pm, droozen wrote:
> I'm a bit confused about your question. You ask a question and then
> pretty much answer it. :) There's other ways, as you say, but that's
> pretty much how you do it in java, too.
>
> x = 124.5
> y = x - int(x) (so now y = 0.5 and x = 124.5)
> z = x - y (so z = 124.0
>
> a = y * 3 ( a now = 1.5 )
> b = z + a ( here's you're only error. 124 + 1.5 will give you b =
> 125.5, unless you are casting it to an int)
>
> Some other ways.
>
> String myX = Double.toString(x); (gives you x as a string)
> String s = myX.substring(myX.indexOf(".") + 1) (s = everything after
> the .)
> String r = myX.substring(0, myX.indexOf(".") (r = everything before
> the .)
>
> a = Double.parseDouble(s) * 3 (Turn everything after the . back into a
> double and multiply)
> b = Double.parseDouble(r) + a (And turn everything before the . back
> into a number and finish your calc
>
> Of course, using string manipulation like this you'll have to have a
> lot more checks for nulls and whatnot (what if there is no decimal
> part, converting it to a string might not yield a . in the string).
>
> Best way is as you posted, though.
>
> On Mar 20, 10:36 pm, Jintsubo wrote:
>
> > So I having a good crack at my first Android app, I've completed all
> > the tutorials and suddenly realised I haven't a clue about how to do
> > simple mathematics in Java. I have some (self taught) experience in
> > PHP, Python etc, I'm no expert but I have managed to get the things
> > done that I want to do.
>
> > What I can do in Python but can't for the life of me figure out in
> > javndroid; how to separate the decimal from the whole.
>
> > for example, 124.50. I want to do some calcs using only the 0.50 and
> > then when I'm finished, add it back onto the 124.0.
>
> > x = 124.50
> > y = x - int(x) (there are other ways but for simplicity sake)... y =
> > 0.50
> > z = x - y = 124.0
>
> > a = y * 3 = 1.5
> > b = z + a = 125.0
>
> > Any pointers greatly appreciated.
>
> > JR
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[android-beginners] Re: separating the decimal from the whole?
I'm a bit confused about your question. You ask a question and then
pretty much answer it. :) There's other ways, as you say, but that's
pretty much how you do it in java, too.
x = 124.5
y = x - int(x) (so now y = 0.5 and x = 124.5)
z = x - y (so z = 124.0
a = y * 3 ( a now = 1.5 )
b = z + a ( here's you're only error. 124 + 1.5 will give you b =
125.5, unless you are casting it to an int)
Some other ways.
String myX = Double.toString(x); (gives you x as a string)
String s = myX.substring(myX.indexOf(".") + 1) (s = everything after
the .)
String r = myX.substring(0, myX.indexOf(".") (r = everything before
the .)
a = Double.parseDouble(s) * 3 (Turn everything after the . back into a
double and multiply)
b = Double.parseDouble(r) + a (And turn everything before the . back
into a number and finish your calc
Of course, using string manipulation like this you'll have to have a
lot more checks for nulls and whatnot (what if there is no decimal
part, converting it to a string might not yield a . in the string).
Best way is as you posted, though.
On Mar 20, 10:36 pm, Jintsubo wrote:
> So I having a good crack at my first Android app, I've completed all
> the tutorials and suddenly realised I haven't a clue about how to do
> simple mathematics in Java. I have some (self taught) experience in
> PHP, Python etc, I'm no expert but I have managed to get the things
> done that I want to do.
>
> What I can do in Python but can't for the life of me figure out in
> javndroid; how to separate the decimal from the whole.
>
> for example, 124.50. I want to do some calcs using only the 0.50 and
> then when I'm finished, add it back onto the 124.0.
>
> x = 124.50
> y = x - int(x) (there are other ways but for simplicity sake)... y =
> 0.50
> z = x - y = 124.0
>
> a = y * 3 = 1.5
> b = z + a = 125.0
>
> Any pointers greatly appreciated.
>
> JR
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