HI lily, for the colouring of individual points you can set the colour aesthetic. The ID is numeric so ggplot applies a colour scale. If we cast ID to a factor we get the appropriate colouring.
test_df <- data.frame(ID = 1:20, v1 = rnorm(20), v2 = rnorm(20), v3 = rnorm(20)) ggplot(data=test_df, aes(x=v1,y=v2, colour = as.factor(ID))) + geom_point()+ theme_bw()+ xlab('Variable 1')+ ylab('Variable 2') How to choose a number of samples from the dataset you can use the subset function to select by some variable: sub_test_df1 <- subset(test_df, ID < 5) ggplot(data=sub_test_df1, aes(x=v1,y=v2, colour = as.factor(ID))) + geom_point()+ theme_bw()+ xlab('Variable 1')+ ylab('Variable 2') Or sample a number of random rows using samle() if this is your intention. sub_test_df2 <- test_df[sample(x = 1:nrow(test_df), size = 10), ] ggplot(data=sub_test_df2, aes(x=v1,y=v2, colour = as.factor(ID))) + geom_point()+ theme_bw()+ xlab('Variable 1')+ ylab('Variable 2') HTH Ulrik On Fri, 25 Aug 2017 at 21:38 lily li <chocol...@gmail.com> wrote: > Hi R users, > > I have some sets of variables and put them into one dataframe, like in the > following. How to choose a specific set of pareto front, such as 10 from > the current datasets (which contains more than 100 sets)? And how to show > the 10 points on one figure with different colors? I can put all the points > on one figure though, and have the code below. I drew two ggplots to show > their correlations, but I want v1 and v3 to be as close as 1, v2 to be as > close as 0. Thanks very much. > > DF > > ID v1 v2 v3 > 1 0.8 0.1 0.7 > 2 0.85 0.3 0.6 > 3 0.9 0.21 0.7 > 4 0.95 0.22 0.8 > 5 0.9 0.3 0.7 > 6 0.8 0.4 0.76 > 7 0.9 0.3 0.77 > ... > > fig1 = ggplot(data=DF, aes(x=v1,y=v2))+ geom_point()+ theme_bw()+ > xlab('Variable 1')+ ylab('Variable 2') > print(fig1) > > fig2 = ggplot(data=DF, aes(x=v1,y=v3)+ geom_point()+ theme_bw()+ > xlab('Variable 1')+ ylab('Variable 3') > print(fig2) > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.