identifying what labels have been created in a plot
on 01/30/2009 10:51 AM Dennis Fisher wrote:
Colleagues R 2.8.0; OS X, Vista, Ubuntu Linux In some instances, when I create a graphic using plot(XVAR, YVAR), it would be valuable to know the values that R will display on the y-axis (e.g., if the range of data is 0-70, it might display 0, 10, 30, 50, 70). Is there a simple means to access these values? Also, in some instances, additional ticks appear between the displayed values (in this case, at 20, 40, 60). Can I obtain the list of the positions of all ticks? Access to this information permits me to tailor the ticks and labels in a particular manner. Thanks for any suggestions. Dennis
See ?axis, where in the Details, it will lead you to ?axTicks plot(c(0, 70), c(0, 70)) # Y axis tick marks
axTicks(2)
[1] 0 10 20 30 40 50 60 70 pretty() will also get you similar information, save when using log scaling:
pretty(c(0, 70))
[1] 0 10 20 30 40 50 60 70 Keep in mind that you can always explicitly call axis() using the 'at' argument to specify the locations of the tick marks and labels, after plotting something without the axes being drawn by default. HTH, Marc Schwartz