Converting a Sequence to Monotonically Increasing Sequence

[hansmuller]

Hi, I have a variable X with the sequence of number such as: 3, 4, 6, 5, 4, 7, 9, 7, 8, 9, 10. I need to create a new variable Y so that Yi=max(Xi, Yi-1). It would become a sequence like: 3, 4, 6, 6, 6, 7, 9, 9, 9, 9, 10. How can I do the programming to get this new variable? Thank you so much for your suggestion. 

[FreelanceReinh]

Hi @hansmuller,

Apply the RETAIN statement to y:

data have;
infile cards dsd;
input x @@;
cards;
3, 4, 6, 5, 4, 7, 9, 7, 8, 9, 10
;

data want;
set have;
y=max(x,y);
retain y;
run;

[ed_sas_member · Accepted solution]

Hi @hansmuller 

I am thinking about something like this, using the RETAIN function:

data want;
	set have;
	retain y;
	if x >= y then y=x;
run;

[hansmuller]

Thank you so much!

[Jagadishkatam]

Alternatively with ifn and retain

data want;
set have;
retain new;
new=ifn(x<new,new,x);
run;