lets_plot.geom_qq_line

lets_plot.geom_qq_line(mapping=None, *, data=None, stat=None, position=None, show_legend=None, sampling=None, tooltips=None, distribution=None, dparams=None, quantiles=None, **other_args)

Display quantile-quantile fitting line.

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 DataFrame 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=’qq_line’

The statistical transformation to use on the data for this layer, as a string. Supported transformations: ‘identity’ (leaves the data unchanged), ‘qq_line’ (compare two probability distributions), ‘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

Position adjustment, either as a string (‘identity’, ‘stack’, ‘dodge’, …), or the result of a call to a position adjustment function.

show_legendbool, default=True

False - do not show legend for this layer.

samplingFeatureSpec

Result of the call to the sampling_xxx() function. Value None (or ‘none’) will disable sampling for this layer.

tooltipslayer_tooltips

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

distribution{‘norm’, ‘uniform’, ‘t’, ‘gamma’, ‘exp’, ‘chi2’}, default=’norm’

Distribution function to use.

dparamslist

Additional parameters (of float type) passed on to distribution function. If distribution is ‘norm’ then dparams is a pair [mean, std] (=[0.0, 1.0] by default). If distribution is ‘uniform’ then dparams is a pair [a, b] (=[0.0, 1.0] by default). If distribution is ‘t’ then dparams is an integer number [d] (=[1] by default). If distribution is ‘gamma’ then dparams is a pair [alpha, beta] (=[1.0, 1.0] by default). If distribution is ‘exp’ then dparams is a float number [lambda] (=[1.0] by default). If distribution is ‘chi2’ then dparams is an integer number [k] (=[1] by default).

quantileslist, default=[0.25, 0.75]

Pair of quantiles to use when fitting the Q-Q line.

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

The Q-Q line plot is used for comparing two probability distributions (sample and theoretical) by plotting line passed through the pair of corresponding quantiles.

Computed variables:

  • ..theoretical.. : theoretical quantiles.

  • ..sample.. : sample quantiles.

geom_qq_line() understands the following aesthetics mappings:

  • sample : y-axis value.

  • alpha : transparency level of a layer. Understands numbers between 0 and 1.

  • color (colour) : color of a geometry. Can be continuous or discrete. For continuous value this will be a color gradient between two colors.

  • linetype : type of the line. Codes and names: 0 = ‘blank’, 1 = ‘solid’, 2 = ‘dashed’, 3 = ‘dotted’, 4 = ‘dotdash’, 5 = ‘longdash’, 6 = ‘twodash.

  • size : line width.

Examples

1import numpy as np
2from lets_plot import *
3LetsPlot.setup_html()
4n = 100
5np.random.seed(42)
6sample = np.random.normal(0, 1, n)
7ggplot({'sample': sample}, aes(sample='sample')) + geom_qq() + geom_qq_line()