how to replace blank cells with a numerical value in histogram?

[Armand]

Hello

is there a way to replace blank cells with -1 in my graph code below (Product_rating field has blank cells so need to replace that with -1):

axis1 label=None;

axis2 label=('Product_rating') order=(-1 to 20 by 2);

title 'Product rating';

proc gchart data=Prod_list;

vbar3D product_rating/ discrete noframe

                                   subgroup=product_class

raxis=axis1 maxis=axis2

autoref clipref cref=graybb

coutline=black woutline=1;

run;

quit;

[Armand]

i did find a way to work around the blank cells by replacing the blank cell in the field '"Product_rating" by -1 before proceeding to the graph.