R help - Feb 2015 - Difference in dates for unique ID

HI Farnoosh,



Not sure I understand the expected output.  The difference between the first 2
days is "136 days"

May be this helps

   library(data.table)
       dcast.data.table(setDT(df)[, list(Visit=.N, Diff=
as.numeric(abs(diff(as.Date(Date, format='%d-%b-%y'))))) ,
         by = ID], ID+Visit~ Diff, value.var='Diff', length)

    ID Visit 136 255 857
     1:  1     2   1   0   0
     2:  2     3   0   1   1





On Wednesday, February 11, 2015 5:47 PM, farnoosh sheikhi <farnoosh_81 at
yahoo.com> wrote:



Hi Arun,

I have a data set that look s like below. I wanted to get a difference in dates
for each unique ID and record it as a new X and have binary input for each one.

ID   Date
1        06-Sep-13
1        20-Jan-14
2        06-Mar-12
2        25-Jun-11
2        29-Oct-13



For example for the first two date for ID=1 ( 20-Jan-14 - 06-Sep-13 ~ 121) and I
want the data to be like follow:

ID  Visit   121
1       2        1
2       3         0


I really appreciate if you can help me with this. I know I need to write some
kind of loop, but I don't know how to think of the logic behind it.
Thanks a lot.



Farnoosh

That's exactly what I was thinking. Thanks tons.

Sent from Yahoo Mail on Android

From:"arun" <smartpink111 at yahoo.com>
Date:Sun, Feb 15, 2015 at 2:47 AM
Subject:Re: Difference in dates for unique ID

HI Farnoosh,



Not sure I understand the expected output.? The difference between the first 2
days is "136 days"

May be this helps

? library(data.table)
? ? ? dcast.data.table(setDT(df)[, list(Visit=.N, Diff=
as.numeric(abs(diff(as.Date(Date, format='%d-%b-%y'))))) ,
? ? ? ? by = ID], ID+Visit~ Diff, value.var='Diff', length)

? ? ID Visit 136 255 857
? ? 1:? 1? ? 2? 1? 0? 0
? ? 2:? 2? ? 3? 0? 1? 1







On Wednesday, February 11, 2015 5:47 PM, farnoosh sheikhi <farnoosh_81 at
yahoo.com> wrote:



Hi Arun,

I have a data set that look s like below. I wanted to get a difference in dates
for each unique ID and record it as a new X and have binary input for each one.

ID? Date
1? ? ? ? 06-Sep-13
1? ? ? ? 20-Jan-14
2? ? ? ? 06-Mar-12
2? ? ? ? 25-Jun-11
2? ? ? ? 29-Oct-13



For example for the first two date for ID=1 ( 20-Jan-14 - 06-Sep-13 ~ 121) and I
want the data to be like follow:

ID? Visit? 121
1? ? ? 2? ? ? ? 1
2? ? ? 3? ? ? ? 0


I really appreciate if you can help me with this. I know I need to write some
kind of loop, but I don't know how to think of the logic behind it.
Thanks a lot.



Farnoosh


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