Main Content

cdflib.getVarData

Single value from record in variable

Syntax

datum = cdflib.getVarData(cdfId,varNum,recNum,indices)
datum = cdflib.getVarData(cdfId,varNum,recNum)

Description

datum = cdflib.getVarData(cdfId,varNum,recNum,indices) returns a single value from a variable in a Common Data Format (CDF) file.

datum = cdflib.getVarData(cdfId,varNum,recNum) returns a single value from a variable with no dimensions in a Common Data Format (CDF) file.

Input Arguments

cdfId

Identifier of a CDF file, returned by a call to cdflib.create or cdflib.open.

varNum

Numeric value identifying the variable containing the datum. Variable numbers are zero-based.

recNum

Numeric value identifying the location of the datum in the variable. In CDF terminology, this is called the record number. Record numbers are zero-based.

indices

Array of dimension indices within the record. Dimension indices are zero-based. If the variable has no dimensions, you can omit this parameter.

Output Arguments

datum

Value of the specified record.

Examples

Open the example CDF file and retrieve data associated with a variable:

cdfId = cdflib.open("example.cdf");

% Determine how many variables are in the file
info = cdflib.inquire(cdfId);
numVars = info.numVars
numVars =

     6
% Determine if the first variable has dimensions
varnum = 0;
varinfo = cdflib.inquireVar(cdfId,varnum);
vardims = varinfo.dims
vardims =

     []
% Get first data record from variable, without specifying dimensions
recnum = 0;
datum = cdflib.getVarData(cdfId,varnum,recnum)
datum =

   6.3146e+13
% Get dimensions of another variable in file
varnum = 3;
varinfo = cdflib.inquireVar(cdfId,varnum);
vardims = varinfo.dims
vardims =

     4     2     2
% Retrieve the first datum in the record (indices are zero-based)
datum = cdflib.getVarData(cdfId,varnum,recnum,[0 0 0])
datum =

    30
% Clean up
cdflib.close(cdfId)
clear cdfId

References

This function corresponds to the CDF library C API routine CDFgetzVarData.

To use this function, you must be familiar with the CDF C interface. You can access the CDF documentation at the CDF website.

Version History

expand all