Statistical Graphics

Bar Charts

You can use the BAR subroutine to create a bar chart. The required argument is a vector that contains values of a discrete variable. These values are used to form the categories of a bar chart. The following statements read the Origin and Type variables from a subset of the Sashelp.Cars data set: 

proc iml;
use Sashelp.Cars where(type ? {"SUV" "Truck" "Sedan"});
read all var {origin type};
close Sashelp.Cars;

The following statements create a simple bar chart of the Origin variable, which is shown in Figure 15.2: 

title "Bar Chart with Default Properties";
call Bar(origin);

Figure 15.2: Bar Chart

Bar Chart


For a more complicated example, the following statements create a bar chart by using the TYPE=, GROUP=, GROUPOPT=, GRID=, and LABEL= options. The result is shown in Figure 15.3. 

title "Horizontal Bar Chart, group and order categories";
call Bar(origin) type="HBar" group=type groupopt="Cluster"
         grid="X" label="Origin";

Figure 15.3: Clustered Bar Chart

Clustered Bar Chart


The following list explains the options that are used to create Figure 15.3:

  • The TYPE= option specifies whether to create a vertical bar chart or a horizontal bar chart. Figure 15.3 shows a horizontal bar chart.

  • The GROUP= option specifies a vector of values that determine groups in the plot. Figure 15.3 shows the bar chart grouped according to a subset of values for the Type variable.

  • The GROUPOPT= option specifies a character vector of values that determine how groups are displayed. Figure 15.3 shows a clustered bar chart.

  • The GRID= option specifies whether grid lines are displayed for the X and Y axes. Figure 15.3 shows grid lines for the X axis.

  • The LABEL= option specifies axis labels for the X or Y axis. Figure 15.3 shows that the label "Origin" is used for the X axis.