topic Re: Changing dates by Individuals in Statistical Procedures

Changing dates by Individuals

elfkitty12 — Sun, 13 Jan 2013 22:02:09 GMT

I have a dataset that looks like the following:

ID          Use_Date          Other Variables
Bob       14Jan2012
Bob       24Jan2012
Bob       31Jan2012

Joe 13Jan2012

Joe       25Jan2012
Phil       10Jan2012
Phil       11Jan2012

Phil 23Jan2012

I want to create a new variable, say fixed_date. Fixed_date will be zero for the earliest occuring observation (for each individual). For the other observations (for each individual), fixed_date will be the # of days after that earliest occurance. So I want it to look like this:

ID          Use_Date          Fixed_Date
Bob       14Jan2012          0
Bob       24Jan2012          10
Bob       31Jan2012          17

Joe 13Jan2012 0

Joe       25Jan2012          12
Phil       10Jan2012          0
Phil       11Jan2012          1

Phil 23Jan2012 13

Can anyone help me do this? Thank you!!!

Re: Changing dates by Individuals

elfkitty12 — Sun, 13 Jan 2013 22:03:19 GMT

occurence** I can't spell!

Re: Changing dates by Individuals

Linlin — Sun, 13 Jan 2013 22:11:13 GMT

data have;

input ID $ Use_Date : date9.;

format use_date date9.;

cards;

Bob 14Jan2012

Bob 24Jan2012

Bob 31Jan2012

Joe 13Jan2012

Joe 25Jan2012

Phil 10Jan2012

Phil 11Jan2012

Phil 23Jan2012

;

proc sort data=have;by id use_date;

data want;

retain d1;

set have;

by id;

if first.id then do; d1=use_date;fixed_date=0;end;

else fixed_date=use_date-d1;

drop d1;

proc print;run;

fixed_

Obs ID Use_Date date

1 Bob 14JAN2012 0

2 Bob 24JAN2012 10

3 Bob 31JAN2012 17

4 Joe 13JAN2012 0

5 Joe 25JAN2012 12

6 Phil 10JAN2012 0

7 Phil 11JAN2012 1

8 Phil 23JAN2012 13

Re: Changing dates by Individuals

elfkitty12 — Mon, 14 Jan 2013 02:26:15 GMT

perfect! thank you!