yline — Draw horizontal reference lines on the current axes.

yline adds one or more horizontal reference lines to the current axes. It accepts scalar or vector y-coordinates, MATLAB line specs, labels, and common line name/value styling such as Color, LineStyle, LineWidth, and DisplayName.

How yline works

• yline(y) adds a horizontal reference line at each coordinate in y.
• Reference lines append to the current axes without replacing existing plot content.
• Line spans follow the active axes limits, including later xlim and ylim changes.
• The returned handle supports get and set for Value, Color, LineWidth, LineStyle, Label, LabelOrientation, DisplayName, and Visible.

Examples

Add a zero baseline

plot(-5:5, (-5:5).^2 - 10);
yline(0, 'k', 'LineWidth', 1);

Expected output:

% Adds a black horizontal reference line at y = 0

Label a baseline

plot(1:10, rand(1, 10));
yline(0.5, ':', 'Baseline', 'LabelOrientation', 'horizontal');

Expected output:

% Adds a dotted labeled horizontal reference line

Related Plotting functions

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