Rounding error on Y-axis when all Y values are zeroes

[duzenko]

I can't get the Y-axis labels right using the latest version of the library
By default they include trailing zeroes:

Now I try to pass a custom number formatter so as to get rid of the zeroes and it works for that data set

                NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
                formatter.maximumSignificantDigits = 3;
                [chart set_defaultValueFormatter:formatter];

But when I pass all zeroes to a line chart I get an ugly rounding error:

Is there another way to get rid of the trailing zeroes, or am I doing something wrong?

[liuxuan30]

have you tried allowRepeatingValue?

[duzenko]

What is that? Can't see it here: https://jitpack.io/com/github/PhilJay/MPAndroidChart/v2.2.5/javadoc/

[liuxuan30]

it's in iOS portion, I am not sure if you can see it on android side

[duzenko]

What class is this method in and what does it do?

[liuxuan30]

should be similar to #315

[duzenko]

Sorry, which of my two problems is this supposed to help? Trailing zeroes or rounding error?
And I can't see this property anywhere

[liuxuan30]

oops, I thought you are having duplicated zeroes. Are you asking about the number formatter？You can take a look at maximumFractionDigits and minimumFractionDigits

[duzenko]

I think I explained my problem in the first post.
There is an ugly rounding error when I use formatter

[liuxuan30]

as I said, maximumFractionDigits and minimumFractionDigits seems solution to me

[duzenko]

Enlighten me - what values do I need to assign to maximumFractionDigits and minimumFractionDigits?

[liuxuan30]

hmm, if you only want max two, like 0.11, it will avoid situation like 0.111111111111.
if you need minimum digits like 2, "1" would be "1.00".
So in your case, I would guess minimumFractionDigits = 0 and maximumFractionDigits = 1 or 2. Does this works for you?

[duzenko]

Regret it does not

Test code

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    LineChartView *chart = [[LineChartView alloc] init];
    chart._defaultValueFormatter.maximumFractionDigits = 2;
    chart._defaultValueFormatter.minimumFractionDigits = 0;
    [self.view addSubview:chart];

    int N = 5, M = 11;
    NSMutableArray *vals = [NSMutableArray arrayWithCapacity:N], *xVals = [NSMutableArray arrayWithCapacity:M];
    for (int i=0; i<M; i++) {
        if (i < N) {
            ChartDataEntry *entry = [[ChartDataEntry alloc] initWithValue:98+i xIndex:vals.count];
            [vals addObject:entry];
        }
        [xVals addObject:[NSNumber numberWithInt:i]];
    }
    LineChartDataSet *dataSet = [[LineChartDataSet alloc] initWithYVals:vals];
    LineChartData *data = [[LineChartData alloc] initWithXVals:xVals dataSet:dataSet];
    [chart setData:data];
    chart.frame = CGRectMake(0, 30, self.view.frame.size.width, 100);
}

Result:

[liuxuan30]

OK first of all, if you see something contains _ as prefix, that's what not usually you should use outside the library, it's private or internal, so nothing guaranteed if you directly use it..
What you should use at y axis is valueFormatter, not _defaultValueFormatter.
If you want the same formatter for value labels, use set.valueFormatter

[duzenko]

Changed to

    chart.leftAxis.valueFormatter.maximumFractionDigits = 2;
    chart.leftAxis.valueFormatter.minimumFractionDigits = 0;

No effect. Same thing as on the picture from the previous post

[liuxuan30]

that's simply not true: I used ChartsDemo and you can see it has 23, 23.16, and 23.2 on the chart.

    ChartYAxis *leftAxis = _chartView.leftAxis;
    leftAxis.labelFont = [UIFont systemFontOfSize:10.f];
    leftAxis.labelCount = 8;
    leftAxis.valueFormatter = [[NSNumberFormatter alloc] init];
    leftAxis.valueFormatter.maximumFractionDigits = 2;
    leftAxis.valueFormatter.minimumFractionDigits = 0;
    leftAxis.valueFormatter.negativeSuffix = @" $";
    leftAxis.valueFormatter.positiveSuffix = @" $";
    leftAxis.labelPosition = YAxisLabelPositionOutsideChart;
    leftAxis.spaceTop = 0.15;
    leftAxis.axisMinValue = 0.0; // this replaces startAtZero = YES

[duzenko]

What is not true? My data are integer numbers and I don't want decimals after dot on the Y axis

[liuxuan30]

look I think it's all about the value formatter you are using... The library will take all values into double type, so even you mean integer, it's still double.

If you don't want decimals, simply set maximumFractionDigits = 0.

you need to take a look at the number formatter documentation, it's all there.

[duzenko]

I need to show values as float if they're float and as integer if they are integer - the data comes from web and I don't know that beforehand

[iamabhiee]

How can I set integers for values label in Horizontal Bar chart?