[R] date calculation

[Shi, Tao]

Hi Phil,

Thanks for the reply, but I don't think you have 
explained where the decimal part is coming from....

...Tao



----- Original Message -----
> From:Phil Spector <spector at stat.berkeley.edu>
> To:"Shi, Tao" <shidaxia at yahoo.com>
> Cc:r-help at stat.math.ethz.ch
> Sent:Friday, October 29, 2010 5:04:23 PM
> Subject:Re: [R] date calculation
> 
> 
> Tao -
    The documentation for the difftime function 
> says:

Function ‘difftime’ calculates a difference of two 
> date/time
      objects and returns an object of class 
> ‘"difftime"’ with an
      attribute indicating the 
> units.

So that answers your question.

If you want it to be an 
> integer, you're certainly free to make it one:

> 
> as.integer(difftime(strptime("24NOV2004", format="%d%b%Y"), 
+    
>                 
> strptime("13MAY2004",format="%d%b%Y"), units="days"))
[1] 195


>                 
>     - Phil Spector
        
>              Statistical Computing 
> Facility
            
>          Department of Statistics

>                 
>      UC Berkeley
        
>             
> ymailto="mailto:spector at stat.berkeley.edu" 
> href="mailto:spector at stat.berkeley.edu">spector at stat.berkeley.edu



On 
> Fri, 29 Oct 2010, Shi, Tao wrote:

> Hi list,
>
> Could 
> someone explain to me why the following result is not a 
> integer?
>
>
>> difftime(strptime("24NOV2004", 
> format="%d%b%Y"), strptime("13MAY2004",
>> format="%d%b%Y"), 
> units="days")
> Time difference of 195.0417 days
>
> I'm using 
> R2.12.0 on WinXP.
>
> Thanks!
>
> ...Tao
>
> 
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