I have three variables A, B & C in the following format

```
A         B     C
Cat1      1    NA       
Cat1      2    NA
Cat1      1    NA
Cat1      2    NA
Cat1      NA   4
Cat1      NA   1
Cat1      NA   6
Cat1      NA   4
Cat1      7    NA       
Cat1      9    NA
Cat1      3    NA
Cat1      2    NA
Cat1      NA   2
Cat1      NA   4 
Cat1      NA   5
Cat1      NA   9
.         .    .
.         .    .        
.         .    .
.         .    .

```

lets say in variable C wherever there are numerical values part from NA, it should be called as one Group and I have to find the difference of maximum & minimum values in that group..Can someone please help

desired Output:

Sure. The desired output be like : A Trips Value

```
                              Cat 1   Trip1      xx (dif of max & min of that trip)                                                       

```