[ncl-talk] how to read off multiple variables from a nc file through one reading operation within a loop

[Karin Meier-Fleischer]

Hi Tabish,

Krishan is right but I want to add something about the use of script variables. 
If you define 

>> var = "E_PM25J"

you have to use var with $...$

>> pm25 = a->$var$(0,0,:,:)

Bye, Karin 


> Am 25.10.2018 um 15:21 schrieb Krishnamoorthy Chandramouli <chandrakrishna.90 at gmail.com>:
> 
> Hi,
> 
> You can use getfilevarnames to read the variable names from nc file .
> Loop over the names and read them.
> 
> 
> Warm regards,
> krishna
> 
> 
> 
>> On Thu, Oct 25, 2018 at 6:46 AM Tabish Ansari <tabishumaransari at gmail.com> wrote:
>> Hi,
>> 
>> I want to read in several variables, in my case emissions of chemical species, from a netcdf file.
>> 
>> There are too many variables in the file, eg- E_PM25I, E_PM25J, E_CO, E_NO2 etc
>> Is it possible to store them in a string array and supply them one by one to the reading function?
>> 
>> Currently, I'm unable to do this due to datatype mismatch.
>> 
>> I'm trying something like this:
>> 
>> begin
>> a=addfile("/data3/tabish/vert-MEIC-emis/APEC-wrfchemi/wrfchemi_00z_d03_total_Oct_8lev_0.5BTHso2_so4_allnormal.nc","r")
>> pm25 = a->E_PM25J(0,0,:,:)
>> ("var read in the normal way")
>> var = "E_PM25J"
>> pm25 = a->var(0,0,:,:)
>> print("var read in dynamic way")
>> end
>> 
>> however, the string variable var isn't used in the reading process.
>> 
>> Please let me know if there's a way in NCL to do this.
>> This will make the algorithm much more efficient.
>> 
>> Cheers,
>> 
>> Tabish
>> 
>> Tabish U Ansari
>> PhD student, Lancaster Environment Center
>> Lancaster Univeristy
>> Bailrigg, Lancaster, 
>> LA1 4YW, United Kingdom
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