geom_hline

geom_hline(mapping=None, *, data=None, stat=None, position=None, show_legend=None, inherit_aes=None, manual_key=None, sampling=None, tooltips=None, yintercept=None, color_by=None, **other_args)

Add a straight horizontal line to the plot.

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=’identity’

The statistical transformation to use on the data for this layer, as a string.

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.

inherit_aesbool, default=True

False - do not combine the layer aesthetic mappings with the plot shared mappings.

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. Set tooltips=’none’ to hide tooltips from the layer.

yinterceptfloat

The value of y at the point where the line crosses the y axis.

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

Define the color 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

geom_hline() understands the following aesthetics mappings:

• yintercept : line y-intercept.

• alpha : transparency level of a layer. Accept values between 0 and 1.

• color (colour) : color of the geometry lines. For more info see Color and Fill.

• size : line width.

• linetype : type of the line. Accept codes or names (0 = ‘blank’, 1 = ‘solid’, 2 = ‘dashed’, 3 = ‘dotted’, 4 = ‘dotdash’, 5 = ‘longdash’, 6 = ‘twodash’), a hex string (up to 8 digits for dash-gap lengths), or a list pattern [offset, [dash, gap, …]] / [dash, gap, …]. For more info see Line Types.

Examples

from lets_plot import *
LetsPlot.setup_html()
ggplot() + geom_hline(yintercept=0)

import numpy as np
import pandas as pd
from lets_plot import *
LetsPlot.setup_html()
n = 100
classes = ['a', 'b', 'c']
np.random.seed(42)
x = np.random.normal(size=n)
y = np.random.normal(size=n)
c = np.random.choice(classes, size=n)
df = pd.DataFrame({'x': x, 'y': y, 'c': c})
bounds_df = pd.DataFrame([(cl, df[df.c == cl].y.max()) for cl in classes], \
                         columns=['c', 'ymax'])
ggplot() + \
    geom_hline(aes(yintercept='ymax', color='c'), \
               data=bounds_df, size=.7, linetype='longdash') + \
    geom_point(aes(x='x', y='y', color='c'), data=df)

from lets_plot import *
LetsPlot.setup_html()
ggplot() + geom_livemap(location=[0, 0], zoom=1) + \
    geom_hline(yintercept=0, size=1, color="red") + \
    ggtitle("Equator")