CDF_VARDELETE

The CDF_VARDELETE procedure deletes a variable from a SINGLE_FILE CDF file. Note that the variable’s entries are also deleted, and that the variables that numerically follow the deleted variable within the CDF file are automatically renumbered. CDF rVariables and zVariables are counted separately within CDF files. Attempting to delete a variable from a MULTI_FILE format CDF file will result in a warning message.

Examples

cid = CDF_CREATE('DEMOvardelete',/SINGLE_FILE)

; Create 3 zVariables and 1 rVariable:

var1_id = CDF_VARCREATE(cid, 'rVAR1', /CDF_FLOAT)

var2_id = CDF_VARCREATE(cid, 'zVAR1', /CDF_INT4, /REC_NOVARY, $

   /ZVARIABLE)

var3_id = CDF_VARCREATE(cid, 'zVAR2', /CDF_CHAR, [2,10], $

   NUMELEM=10, DIM=[5,5])

var4_id = CDF_VARCREATE(cid, 'zVAR3' ,/CDF_REAL8, /ZVARIABLE)

; Check the number of variables:

info = CDF_INQUIRE(cid)

HELP, info.nzvars, info.nvars

; Delete the first and third zvariables:

CDF_VARDELETE, cid, 'zVAR1', /ZVARIABLE

CDF_VARDELETE, cid, 1, /ZVARIABLE

; CAUTION: Remember the variable numbers are zero-based

; and are automatically renumbered.

info = CDF_INQUIRE(cid)

HELP, info.nzvars, info.nvars

varinfo = CDF_VARINQ(cid, 0, /ZVARIABLE)

; check on zVAR2

HELP, varinfo, /STRUCTURE

CDF_DELETE, cid

IDL Output

<Expression>    LONG      =            3

<Expression>    LONG      =            1

<Expression>    LONG      =            1

<Expression>    LONG      =            1

** Structure <400a3b40>, 8 tags, length=48, refs=1:

   IS_ZVAR         INT              1

   NAME            STRING    'zVAR2'

   DATATYPE        STRING    'CDF_CHAR'

   NUMELEM         LONG                10

   RECVAR          STRING    'VARY'

   DIMVAR          BYTE      Array(2)

   ALLOCATERECS    LONG      Array(2)

   DIM             LONG      Array(1)

Syntax

CDF_VARDELETE, Id, Variable [, /ZVARIABLE]

Arguments

Id

The CDF ID of the file containing the Variable to be deleted, returned from a previous call to CDF_OPEN or CDF_CREATE.

Variable

A string containing the name of the variable to be deleted OR the variable number to be deleted. Variable numbers are 0-based in IDL. zVariables and rVariables are counted separately in CDF files.

Keywords

ZVARIABLE

Set this keyword if the Variable is a zVariable and was passed by number. The default is to assume that Variable is an rVariable.

Version History

4.0.1b

Introduced