Reference Guide > D Routines > DT_TO_SEC Function
  

DT_TO_SEC Function
Standard Library function that converts a date/time variable to a double-precision variable containing number of seconds elapsed from a base date.
Usage
result = DT_TO_SEC(dt_var)
Input Parameters
dt_var — A date/time variable.
Returned Value
result — A double-precision variable containing the number of seconds elapsed between the base date and the date(s) contained in dt_var. The value of the base date is maintained in the system variable !DT_Base.
Keywords
Base — A string containing a date, such as “3-27-92”. This is the base date from which the number of elapsed seconds is calculated. Base can be used to override the default value in the system variable !DT_Base.
Date_FmtSpecifies the format of the base date, if passed into the function. Possible values are 1, 2, 3, 4, or 5, as summarized in Possible Date_Fmt Values:
 
Table 5-10: Possible Date_Fmt Values
Value
Format Description
Examples for May 1, 1992
1
MM*DD*[YY]YY
05/01/92
2
DD*MM*[YY]YY
01-05-92
3
ddd*[YY]YY]
122,1992
4
DD*mmm[mmmmmm]*[YY]YY
01/May/92
5
[YY]YY*MM*DD
1992-05-01
where the asterisk (*) represents one of the following separators: dash (–),
slash (/), comma (,), period (.), or colon (:).
For a detailed description of these formats, see the PV‑WAVE User’s Guide.
Discussion
This function is useful for converting date/time values to relative time. The default base date is September 14, 1752.
Example1
Assume that you have created the array date1 that contains the following date/time data:
date1 = [{!DT, 2002,3,27,7,18,57.0000,91140.305,0},$
         {!DT, 2003,3,27,7,18,57.0000,91505.305,0}, $
         {!DT, 2004,3,27,7,18,57.0000,91871.305,0}]
; To find out the number of seconds for each date from
; the default base, September 14, 1752, use:
seconds = DT_TO_SEC(date1)
PRINT, seconds, Format='(F15.1)'
; PV-WAVE prints:
;   7874435937.0
;   7905971937.0
;   7937594337.0
Example 2
Assume that you have created the array date1 that contains the following date/time data:
date1 = [{!DT, 2002,3,27,7,18,57.0000,91140.305,0},$
         {!DT, 2003,3,27,7,18,57.0000,91505.305,0}, $
         {!DT, 2004,3,27,7,18,57.0000,91871.305,0}]
; To find out the number of seconds for each date from 
; January 1, 1970, use:
seconds = DT_TO_SEC(date1, Base='1-1-70', Date_Fmt=1)
PRINT, seconds, Format='(F15.1)'
; PV-WAVE prints the following:
;   1017213537.0
;   1048749537.0
;   1080371937.0
See Also
DT_TO_STR,   DT_TO_VAR,   SEC_TO_DT
System Variables:    !DT_Base
For more information, see the PV‑WAVE User’s Guide.

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