Returns True for every element of the input that is a defined keyword, variable, or function/procedure name.
function isdefined ( idn_names : string ) return_val [dimsizes(idn_names)] : logical
An array of strings of any dimensionality.
For each element in the idn_names list, isdefined returns True if the element is a defined keyword, variable or function/procedure name, and False otherwise. The output of isdefined is a logical array with the same dimensions as idn_names.
In the NCL script below, isd will be equal to (/True, False, True/):
x = 1.5 title = "Temperature" isd = isdefined((/"x","z","title"/))
Since the above example was checking for existing variables, you could have used isvar as well. In the example below, however, isdefined is used to check for additional things that isvar can't handle, like keywords and function/procedure names:
print(isdefined("if")) ; True print(isdefined("elseif")) ; False (bummer, NCL needs an elseif!) print(isdefined("isdefined")) ; True print(isdefined("begin")) ; True