[ferret_users] Ferret Array/variable class detection

Hi Developers,

Is there any function to check an array class ?

for example character classes defined by the POSIX standard

[[:alpha:]] --------> alphabetic characters

[[:alnum:]] -------> alphanumeric characters

[[:digit:]] ------> Numeric characters

[akshay@aix tmp]$ f
     NOAA/PMEL TMAP
     FERRET v6.85
     Linux 2.6.18-371.1.2.el5 64-bit - 11/12/13
     9-Dec-13 09:58

! Numbers

yes? let numerics = {1,2,3,4,5}

! Alpha

yes? let strings = {"1","2","3","4","5"}

yes? list numerics,strings
             X: 0.5 to 5.5
Column 1: NUMERICS is {1,2,3,4,5}
Column 2: STRINGS is {"1","2","3","4","5"}
       NUMERICS STRINGS
1   / 1:   1.000 "1"
2   / 2:   2.000 "2"
3   / 3:   3.000 "3"
4   / 4:   4.000 "4"
5   / 5:   5.000 "5"

yes? list/file=tester.nc/format=cdf/clobber numerics,strings
LISTing to file tester.nc

yes? can var/all

yes? use tester.nc

yes? sh d
     currently SET data sets:
    1> ./tester.nc (default)
name     title                             I         J         K         L         M         N
NUMERICS {1,2,3,4,5}                      1:5       ...       ...       ...       ...       ...
STRINGS {"1","2","3","4","5"}            1:5       ...       ...       ...       ...       ...

yes? list numerics,strings
             DATA SET: ./tester.nc
             X: 0.5 to 5.5
Column 1: NUMERICS is {1,2,3,4,5}
Column 2: STRINGS is {"1","2","3","4","5"}
       NUMERICS STRINGS
1   / 1:   1.000 "1"
2   / 2:   2.000 "2"
3   / 3:   3.000 "3"
4   / 4:   4.000 "4"
5   / 5:   5.000 "5"

yes? list ..varnames
             VARIABLE : ..VARNAMES
             FILENAME : tester.nc
             SUBSET   : 2 points (X)
1   / 1:"NUMERICS"
2   / 2:"STRINGS"

Here I want to create one array say let mask that should contain 0 if ..varnames is numeric class and 1 if its string class (alphanumeric)

I am interested to know how ferret checks internally whether an array is of string class or numeric class ? while displaying this error message "string/numeric data type mix-up"

yes? let myvar = ..varnames
yes? list myvar
             VARIABLE : ..VARNAMES
             FILENAME : tester.nc
             SUBSET   : 2 points (X)
1   / 1:"NUMERICS"
2   / 2:"STRINGS"

I need to create mask, so that if I list myvar and mask, I should get following result

Expected result :

list myvar,myvar
             DATA SET: ./tester.nc
Column 1: MYVAR is ..VARNAMES
Column 2: mask is some expre
             MYVAR     mask
1   / 1: "NUMERICS" 0
2   / 2: "STRINGS"   1

Thanks and Regards,
Akshay Hegde
CSIR-National Institute of Oceanography,
Dona Paula, Panjim, Goa -403004