lets_plot.geom_density#

lets_plot.geom_density(mapping=None, *, data=None, stat=None, position=None, show_legend=None, manual_key=None, sampling=None, tooltips=None, orientation=None, trim=None, kernel=None, adjust=None, bw=None, n=None, fs_max=None, quantiles=None, quantile_lines=None, color_by=None, fill_by=None, **other_args)#

Display kernel density estimate, which is a smoothed version of the histogram.

Parameters:
mappingFeatureSpec

Set of aesthetic mappings created by aes() function. Aesthetic mappings describe the way that variables in the data are mapped to plot “aesthetics”.

datadict or Pandas or Polars DataFrame

The data to be displayed in this layer. If None, the default, the data is inherited from the plot data as specified in the call to ggplot.

statstr, default=’density’

The statistical transformation to use on the data for this layer, as a string. Supported transformations: ‘identity’ (leaves the data unchanged), ‘count’ (counts number of points with same x-axis coordinate), ‘bin’ (counts number of points with x-axis coordinate in the same bin), ‘smooth’ (performs smoothing - linear default), ‘density’ (computes and draws kernel density estimate).

positionstr or FeatureSpec, default=’identity’

Position adjustment. Either a position adjustment name: ‘dodge’, ‘dodgev’, ‘jitter’, ‘nudge’, ‘jitterdodge’, ‘fill’, ‘stack’ or ‘identity’, or the result of calling a position adjustment function (e.g., position_dodge() etc.).

show_legendbool, default=True

False - do not show legend for this layer.

manual_keystr or layer_key

The key to show in the manual legend. Specify text for the legend label or advanced settings using the layer_key() function.

samplingFeatureSpec

Result of the call to the sampling_xxx() function. To prevent any sampling for this layer pass value “none” (string “none”).

tooltipslayer_tooltips

Result of the call to the layer_tooltips() function. Specify appearance, style and content.

orientationstr, default=’x’

Specify the axis that the layer’s stat and geom should run along. Possible values: ‘x’, ‘y’.

trimbool, default=False

If False, each density is computed on the full range of the data. If True, each density is computed over the range of that group.

kernelstr, default=’gaussian’

The kernel we use to calculate the density function. Choose among ‘gaussian’, ‘cosine’, ‘optcosine’, ‘rectangular’ (or ‘uniform’), ‘triangular’, ‘biweight’ (or ‘quartic’), ‘epanechikov’ (or ‘parabolic’).

bwstr or float

The method (or exact value) of bandwidth. Either a string (choose among ‘nrd0’ and ‘nrd’), or a float.

adjustfloat

Adjust the value of bandwidth by multiplying it. Changes how smooth the frequency curve is.

nint, default=512

The number of sampled points for plotting the function.

fs_maxint, default=500

Maximum size of data to use density computation with ‘full scan’. For bigger data, less accurate but more efficient density computation is applied.

quantileslist of float, default=[0.25, 0.5, 0.75]

Draw horizontal lines at the given quantiles of the density estimate.

quantile_linesbool, default=False

Show the quantile lines.

color_by{‘fill’, ‘color’, ‘paint_a’, ‘paint_b’, ‘paint_c’}, default=’color’

Define the color aesthetic for the geometry.

fill_by{‘fill’, ‘color’, ‘paint_a’, ‘paint_b’, ‘paint_c’}, default=’fill’

Define the fill aesthetic for the geometry.

other_args

Other arguments passed on to the layer. These are often aesthetics settings used to set an aesthetic to a fixed value, like color=’red’, fill=’blue’, size=3 or shape=21. They may also be parameters to the paired geom/stat.

Returns:
LayerSpec

Geom object specification.

Notes

Computed variables:

  • ..density.. : density estimate (mapped by default).

  • ..count.. : density * number of points.

  • ..scaled.. : density estimate, scaled to maximum of 1.

  • ..quantile.. : quantile estimate.

geom_density() understands the following aesthetics mappings:

Examples

1import numpy as np
2from lets_plot import *
3LetsPlot.setup_html()
4np.random.seed(42)
5x = np.random.normal(size=1000)
6ggplot({'x': x}, aes(x='x')) + geom_density()

1import numpy as np
2from lets_plot import *
3LetsPlot.setup_html()
4n = 200
5np.random.seed(42)
6ggplot({'x': np.random.normal(size=n)}) + \
7    geom_density(aes(x='x', fill='..quantile..'), color='black', size=1, \
8                 quantiles=[0, .02, .1, .5, .9, .98, 1], quantile_lines=True)

 1import numpy as np
 2from lets_plot import *
 3LetsPlot.setup_html()
 4n = 300
 5np.random.seed(42)
 6x = np.random.normal(size=n)
 7c = np.random.choice(['a', 'b', 'c'], size=n)
 8ggplot({'x': x, 'c': c}, aes(x='x')) + \
 9    geom_density(aes(group='c', color='c', fill='c'), alpha=.2, \
10                 tooltips=layer_tooltips().format('..density..', '.3f')\
11                                          .line('density|@..density..')\
12                                          .format('..count..', '.1f')\
13                                          .line('count|@..count..')\
14                                          .format('..scaled..', '.2f')\
15                                          .line('scaled|@..scaled..'))

 1import numpy as np
 2from lets_plot import *
 3LetsPlot.setup_html()
 4np.random.seed(42)
 5x = np.random.normal(size=1000)
 6p = ggplot({'x': x}, aes(x='x'))
 7bunch = GGBunch()
 8for i, bw in enumerate([.1, .2, .4]):
 9    for j, n in enumerate([16, 64, 256]):
10        bunch.add_plot(p + geom_density(kernel='epanechikov', bw=bw, n=n) + \
11                           ggtitle('bw={0}, n={1}'.format(bw, n)),
12                       j * 300, i * 200, 300, 200)
13bunch.show()

 1import numpy as np
 2from lets_plot import *
 3LetsPlot.setup_html()
 4np.random.seed(42)
 5x = np.random.normal(size=1000)
 6y = np.sign(x)
 7p = ggplot({'x': x, 'y': y}, aes(x='x'))
 8bunch = GGBunch()
 9for i, adjust in [(i, .5 * (1 + i)) for i in range(3)]:
10    bunch.add_plot(p + geom_density(aes(weight='y'), kernel='cosine', \
11                                    adjust=adjust) + \
12                       ggtitle('adjust={0}'.format(adjust)),
13                   i * 300, 0, 300, 200)
14bunch.show()