NCDF_ATTINQ
The NCDF_ATTINQ function returns a structure that contains information about a NetCDF attribute. This structure, described below, has the form:
{ DATATYPE:'', LENGTH:0L }
Examples
id = NCDF_CREATE('test.nc', /CLOBBER) ; Open a new NetCDF file.
id2 = NCDF_CREATE('test2.nc', /CLOBBER) ; Open a second file.
; Create two global attributes TITLE and DATE:
NCDF_ATTPUT, id, /GLOBAL, 'TITLE', 'MY TITLE'
NCDF_ATTPUT, id, /GLOBAL, 'DAY', 'July 1,1996'
; Suppose we wanted to use DATE instead of DAY. We could use
; ATTRENAME to rename the attribute:
NCDF_ATTRENAME, id, 'DAY', 'DATE', /GLOBAL
; Next, copy both attributes into a duplicate file:
result = NCDF_ATTCOPY(id, 'TITLE', id2, /IN_GLOBAL, /OUT_GLOBAL)
result2 = NCDF_ATTCOPY(id, 'DATE', id2, /IN_GLOBAL, /OUT_GLOBAL)
; Put the file into data mode:
NCDF_CONTROL, id, /ENDEF
; Get the second attribute’s name:
name = NCDF_ATTNAME(id, /GLOBAL, 1)
; Retrieve the date:
NCDF_ATTGET, id, /GLOBAL, name, date
; Get info about the attribute:
result = NCDF_ATTINQ(id, /GLOBAL, name)
HELP, name, date, result, /STRUCTURE
PRINT, date
PRINT, STRING(date)
NCDF_CLOSE, id ; Close the NetCDF files.
NCDF_CLOSE, id2
IDL Output
NAME STRING = 'DATE'
DATE BYTE = Array(12)
** Structure <400dac30>, 2 tags, length=12, refs=1:
DATATYPE STRING 'BYTE'
LENGTH LONG 12
Note the length includes the NCDF standard NULL terminator
74 117 108 121 32 49 44 49 57 57 54 0
July 1,1996
Syntax
Result = NCDF_ATTINQ( Cdfid [, Varid] , Name [, /GLOBAL])
Return Value
The structure returned by this function contains the following tags:
|
Tag |
Description |
|
DataType |
A string describing the data type of the variable. The string will be one of the following: BYTE, CHAR, INT, LONG, FLOAT, or DOUBLE. |
|
Length |
The number of values stored in the attribute. If the attribute is a string, the number of values indicates one more character than the string length to include the terminating null character. This is the NetCDF convention, as demonstrated in the following example. |
Arguments
Cdfid
The NetCDF ID, returned from a previous call to NCDF_OPEN, NCDF_CREATE, or NCDF_GROUPDEF.
Varid
The NetCDF variable ID, returned from a previous call to NCDF_VARDEF or NCDF_VARID, or the name of the variable. If the GLOBAL keyword is set, this argument must be omitted.
Name
A scalar string containing the name of the attribute for which information is to be returned.
Keywords
GLOBAL
Set this keyword to inquire about a global variable. If this keyword is set, the Varid argument must be omitted.
Version History
|
Pre 4.0 |
Introduced |