Bar Graphs - R Graphics - page 23

Figure 3-1. Bar graph of values (with stat="identity”) with a discrete x-axis

Discussion
When x is a continuous (or numeric) variable, the bars behave a little differently. Instead of hav-
ing one bar at each actual x value, there is one bar at each possible x value between the minimum
and the maximum, as in Figure 3-2 . You can convert the continuous variable to a discrete vari-
able by using factor() :

# There's no entry for Time == 6
BOD

Time demand
1 8.3

2 10.3

3 19.0

4 16.0

5 15.6