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Plotting a subset of a data frame in R is done by first subsetting the data frame using the subset() function, then using the plot() function to create a plot of the subsetted data. Both of these functions take arguments which allow you to specify which columns and rows of the data frame to plot. Once the plot is created, additional modifications can be made to the plot appearance using the various graphical parameters available in the plot() function.
You can use the following methods to plot a subset of a data frame in R:
Method 1: Plot Subset of Data Frame Based on One Condition
#plot var1 vs. var2 where var3 is less than 15 with(df[df$var3 < 15,], plot(var1, var2))
Method 2: Plot Subset of Data Frame Based on Multiple Conditions
#plot var1 vs. var2 where var3 is less than 15 and var4 is greater than 3 with(df[(df$var3 < 15) & (df$var4 > 3),], plot(var1, var2))
The following examples show how to use each method in practice with the following data frame:
#create data frame df <- data.frame(A=c(1, 3, 3, 4, 5, 7, 8), B=c(3, 6, 9, 12, 15, 14, 10), C=c(10, 12, 14, 14, 17, 19, 20), D=c(5, 7, 4, 3, 3, 2, 1)) #view data frame df A B C D 1 1 3 10 5 2 3 6 12 7 3 3 9 14 4 4 4 12 14 3 5 5 15 17 3 6 7 14 19 2 7 8 10 20 1
Example 1: Plot Subset of Data Frame Based on One Condition
The following code shows how to create a scatter plot of variable A vs. variable B where variable C is less than 15:
#plot A vs. B where C is less than 15 with(df[df$C < 15,], plot(A, B))
Notice that only the rows in the data frame where variable C is less than 15 are shown in the plot.
Example 2: Plot Subset of Data Frame Based on Multiple Conditions
The following code shows how to create a scatter plot of variable A vs. variable B where variable C is less than 15 and variable D is greater than 3:
#plot A vs. B where C is less than 15 and D is greater than 3 with(df[(df$C< 15) & (df$D> 3),], plot(A, B))
Notice that only the rows in the data frame where variable C is less than 15 and variable D is greater than 3 are shown in the plot.
The following tutorials explain how to perform other common tasks in R: