[R] Fwd: Dates Conversion/write.foreign

[Shubha Karanth]

---------- Forwarded message ----------
From: Shubha Vishwanath Karanth <shubhak at ambaresearch.com>
Date: Nov 24, 2006 7:54 PM
Subject: Dates Conversion/write.foreign
To: Shubha Karanth <shubhakaranth at gmail.com>, Shubha Vishwanath
Karanth <shubhak at ambaresearch.com>




Hi R experts,



I need an urgent help...



I have an a dataframe caled idat. Below i give a snapshot of it.



                                   Datetime                 Volume_a
    Volume_b



(11/21/06 12:50:00) (11/21/06 12:50:00)               0                0

(11/21/06 13:00:00) (11/21/06 13:00:00)               0                0

(11/21/06 13:10:00) (11/21/06 13:10:00)               0                0

(11/21/06 13:20:00) (11/21/06 13:20:00)               0                0

(11/21/06 13:30:00) (11/21/06 13:30:00)          342113             0

(11/21/06 13:40:00) (11/21/06 13:40:00)          695071             0

(11/21/06 13:50:00) (11/21/06 13:50:00)          470943          4690

(11/21/06 14:00:00) (11/21/06 14:00:00)          870072             0

(11/21/06 14:10:00) (11/21/06 14:10:00)         1010101          2000

(11/21/06 14:20:00) (11/21/06 14:20:00)          714287            50

(11/21/06 14:30:00) (11/21/06 14:30:00)          388716          1780

(11/21/06 14:40:00) (11/21/06 14:40:00)          380038          1245



The type of each variable is given below:





idat : 'data.frame':    144 obs. of  3 variables:

 $ Datetime           :Classes 'chron', 'dates', 'times'  atomic
[1:144] 13473 13473 13473 13473 13473 ...

 $ Volume_a           : num  0 0 0 0 0 0 0 0 0 0 ...

 $ Volume_b           : num  0 0 0 0 0 0 0 0 0 0 ...





The variable i am interested is "Datetime".



I exported this dataframe into SAS by the write.foreign command,



write.foreign(idat,"Z:\\New\\idat_d.sas7bdat","Z:New\\idat_c.sas",package="SAS",dataname="f.idat")



When I export, i see only the date value (Note: no time) in my SAS
data set. Why is this?



The write.foreign package says:



"Numeric variables and factors are supported for all packages, dates
and times (Date, dates, date, and POSIXt classes) are also supported
for SAS and characters are supported for SPSS."



So, what should i do to get my time value also apart from the
datevalue? Do i need to convert the chron object, "Datetime" into
POSIXt...or anything alse...so that SAS can read it as datetime.
format?





Thank you,

Shubha.