# [gradsusr] if and while loop

Fri May 5 15:35:54 EDT 2017

```Dear GrADS Users,

I am trying to use if and while loop. I am interested in counting the
number of times the difference variable (DF) is not equal to zero. I wrote
following script, there is no error but it seems it is not working fine.
Please suggest what could be wrong?

After opening my GrADS readable file, I calculated the value of a
difference variable DF for 15 times. I need to see how many times this
variable is giving value other than zero. I am using following while and if
loop.

'define MV=(DT(t=1)+DT(t=2)+DT(t=3)+DT(t=4))/4'

'define DF1=MV-(DT(t=5)+DT(t=6)+DT(t=7)+DT(t=8))/4'

'define DF2=MV-(DT(t=1)+DT(t=3)+DT(t=5)+DT(t=7))/4'

'define DF3=MV-(DT(t=2)+DT(t=3)+DT(t=4)+DT(t=5))/4'

'define DF4=MV-(DT(t=1)+DT(t=4)+DT(t=5)+DT(t=7))/4'

'define DF6=MV-(DT(t=5)+DT(t=6)+DT(t=7)+DT(t=8))/4'

'define DF7=MV-(DT(t=1)+DT(t=3)+DT(t=5)+DT(t=7))/4'

'define DF8=MV-(DT(t=2)+DT(t=3)+DT(t=4)+DT(t=5))/4'

'define DF9=MV-(DT(t=1)+DT(t=4)+DT(t=5)+DT(t=7))/4'

'define DF10=MV-(DT(t=2)+DT(t=5)+DT(t=7)+DT(t=9))/4'

'define DF11=MV-(DT(t=1)+DT(t=5)+DT(t=6)+DT(t=7))/4'

'define DF12=MV-(DT(t=3)+DT(t=4)+DT(t=6)+DT(t=7))/4'

'define DF13=MV-(DT(t=4)+DT(t=6)+DT(t=8)+DT(t=9))/4'

'define DF14=MV-(DT(t=1)+DT(t=4)+DT(t=8)+DT(t=9))/4'

'define DF15=MV-(DT(t=1)+DT(t=2)+DT(t=8)+DT(t=9))/4'

count= 0

i=1; while (i<=15)

if (DF'i' !=0)

count=count+1

endif

i=i+1

endwhile

p=count/15
*******************************************************

Thanks,

Mubashar
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