R help - Nov 2009 - Missing and number of days

Hi all,



Assume  that I have a  data set (“xcv”) with several  variables  and some of
the variables have a missing observation  represented by -9 as shown below.
 I want to exclude these observations from the analysis ( as a NA).  Is
there a command that I can do it for the entire data set rather than one by
one for each variable ( tmp <- xcv[xcv$v1 != -9, ])



      V1 v2 v3 v4

11    23  14  -9

12    -9  21   3

     -9   30  41  25

     15   07 -9  10



 and I want the results as follows



      V1    v2     v3      v4

11       23    14     NA

       12   NA    21      3

       NA   30    41     25

        15     07   NA    10





The second question is I want to calculate the number of days between two
dates

    Start           end                 number of days

20020626    20020805             40

20030101    20030421             110



How do I do it in R?


Thanks in advance

	[[alternative HTML version deleted]]

For your first question, I believe that

dat[dat==-9]=NA

should do the trick

For your second, are you dates in the Date() format?  If not, try ?Date

Once you get them in Date format, then you can simply subtract them
 d1 = as.Date('20090604',format="%Y%m%d")
d2 = as.Date('20080604',format="%Y%m%d")
d1-d2
Time difference of 365 days

On Thu, Nov 26, 2009 at 12:30 PM, Val <valkremk at gmail.com>
wrote:
> Hi all,
>
>
>
> Assume ?that I have a ?data set (?xcv?) with several ?variables ?and some
of
> the variables have a missing observation ?represented by -9 as shown below.
> ?I want to exclude these observations from the analysis ( as a NA). ?Is
> there a command that I can do it for the entire data set rather than one by
> one for each variable ( tmp <- xcv[xcv$v1 != -9, ])
>
>
>
> ? ? ?V1 v2 v3 v4
>
> 11 ? ?23 ?14 ?-9
>
> 12 ? ?-9 ?21 ? 3
>
> ? ? -9 ? 30 ?41 ?25
>
> ? ? 15 ? 07 -9 ?10
>
>
>
> ?and I want the results as follows
>
>
>
> ? ? ?V1 ? ?v2 ? ? v3 ? ? ?v4
>
> 11 ? ? ? 23 ? ?14 ? ? NA
>
> ? ? ? 12 ? NA ? ?21 ? ? ?3
>
> ? ? ? NA ? 30 ? ?41 ? ? 25
>
> ? ? ? ?15 ? ? 07 ? NA ? ?10
>
>
>
>
>
> The second question is I want to calculate the number of days between two
> dates
>
> ? ?Start ? ? ? ? ? end ? ? ? ? ? ? ? ? number of days
>
> 20020626 ? ?20020805 ? ? ? ? ? ? 40
>
> 20030101 ? ?20030421 ? ? ? ? ? ? 110
>
>
>
> How do I do it in R?
>
>
> Thanks in advance
>
> ? ? ? ?[[alternative HTML version deleted]]
>
>
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