问题 Is there any function in r that allows the plotting of this kind of scatter plots, which separates the dots by group? Here is what I have done so far: hours = c(0.00 ,-1.78 ,-0.50 ,-2.00 ,-2.80 ,2.00 ,-0.16 ,-0.34 ,1.00 ,1.00 ,2.00 ,-1.34 ,-1.00 ,-1.10 ,-0.43 ,-0.49 ,-0.02 ,-0.91, 0.48 ,2.33 ,1.00 ,0.00 ,1.18 ,1.29 ,-1.07 ,-0.26 ,1.96 ,0.36 ,2.00 ,-0.63 ,-0.80 ,-0.70 ,-2.00 ,1.17 ,0.67 ,-3.00) group = c(1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2) df = data.frame