The legappend function adds new entries to a legend. This is good for making PowerPoint slides, when you may want to start by plotting a few data sets, then add data to your plot one entry at a time. This function eliminates the need to copy and paste the complete legend creation code each time you add a curve to a plot, and alleviates the minor headaches you'd experience if you decided to rearrange the order in which items are plotted.

Description
legappend('new legend entry') appends an existing legend with "new legend entry".

legappend('new entry 1','new entry 2',...,'new entry N') adds several new entries to the legend.

legappend('') deletes the last entry from the legend.

legappend('','',...,'') deletes the last several entries from the legend.

[legend_h,object_h,plot_h,text_strings] = legappend(...) returns legend_h, the handle of the new legend; object_h, handles of the line, patch, and text graphics objects used in the legend; plot_h, handles of the lines and other objects used in the plot; and text_strings, a cell array of the text strings used in the legend. Note that for new legend entries, legappend does not add entries to a current legend, but deletes the current legend and recreates a new one. As a result, the legend handle will change with each new-entry use of legappend. The legend handle does not change when legappend is used to delete an entry.