Hi,
I want to calculate the fractional months between different observations from the prior observations with the same key. For example, for the observations with the key "111", I want to calculate the fractional months seen in Counter "2" vs Counter "1", then the fractional month seen in Counter "3" vs Counter "2", then Counter "4" vs Counter "2", then start over again for next key "118". In excel, it would be like using the formula =DATEDIF(D7,D8,"M")+DATEDIF(D7,D8,"MD")/(365/12). Below is an example of the data set and I want to create the "Months btw Dates" column below. Thanks in advance!
Obs | Key | Counter | Date | Months btw Dates |
1 | 111 | 1 | 1/1/2023 | |
2 | 111 | 2 | 2/5/2023 | 1.13 |
3 | 111 | 3 | 4/7/2023 | 2.07 |
4 | 111 | 4 | 6/10/2023 | 2.10 |
5 | 118 | 1 | 2/10/2023 | |
6 | 118 | 2 | 5/1/2023 | 2.69 |
data have;
infile cards expandtabs truncover;
input Obs Key Counter Date :mmddyy10.;
format date mmddyy10.;
cards;
1 111 1 1/1/2023
2 111 2 2/5/2023
3 111 3 4/7/2023
4 111 4 6/10/2023
5 118 1 2/10/2023
6 118 2 5/1/2023
;
data want;
set have;
lag_date=lag(date);
if key=lag(key) then want=yrdif(lag_date,date,'30/360')*12;
drop lag_date;
run;
I mispoke when I said Counter "4" vs Counter "2". What I meant to say was that I want Counter "4" vs Counter "3"
I dislike the idea of "fractional months", as months are different lengths, and so I recommend you not use "fractional months". The following code will compute the number of days between the dates. You can do with that number of days anything you want.
data have;
input obs key counter date :mmddyy8.;
format date date9.;
cards;
1 111 1 1/1/2023
2 111 2 2/5/2023
3 111 3 4/7/2023
4 111 4 6/10/2023
5 118 1 2/10/2023
6 118 2 5/1/2023
;
data want;
set have;
by key;
prev_date=lag(date);
if first.key then days_between=.;
else days_between=date-prev_date;
drop prev_date;
run;
Please note: we expect data to be presented as working SAS data step code, and not other formats such as the one your provided. I have given an example (and instructions here for more complicated data sets). In your future questions, please provide data as shown.
data have;
infile cards expandtabs truncover;
input Obs Key Counter Date :mmddyy10.;
format date mmddyy10.;
cards;
1 111 1 1/1/2023
2 111 2 2/5/2023
3 111 3 4/7/2023
4 111 4 6/10/2023
5 118 1 2/10/2023
6 118 2 5/1/2023
;
data want;
set have;
lag_date=lag(date);
if key=lag(key) then want=yrdif(lag_date,date,'30/360')*12;
drop lag_date;
run;
Registration is open! SAS is returning to Vegas for an AI and analytics experience like no other! Whether you're an executive, manager, end user or SAS partner, SAS Innovate is designed for everyone on your team. Register for just $495 by 12/31/2023.
If you are interested in speaking, there is still time to submit a session idea. More details are posted on the website.
Learn how use the CAT functions in SAS to join values from multiple variables into a single value.
Find more tutorials on the SAS Users YouTube channel.