The hold function corresponds to the NextPlot property on the Axes.
I realize that's a little confusing - hold has only two states, on or off, but NextPlot has a few more options. All the way at the bottom of the hold documentation page you'll find this text:
The hold function sets these properties:
- NextPlot axes property - Sets this property of the associated Axes, PolarAxes, or GeographicAxes object to either 'add' or 'replace'.
- NextPlot figure property - Sets this property of the Figure object to 'add'.
So the code snippet you're looking for is:
ax.NextPlot = 'add';
There's a small caveat not mentioned in the documentation above, which is that hold off has some slightly different behavior with uiaxes. Instead of setting the NextPlot property to 'replace' it sets it to 'replacechildren'. This can be more useful in apps - it means that the children of the axes will be replaced but the axes will retain other settings. Details about all the different kinds of NextPlot on figure and axes are here:
