S********a
发帖数: 359 | 1 下面是用SAS写的，用R怎么写呢？
data a;
set a;
if yea2=99 then ndays=dob_c1-'31DEC1998'd;
else if yea2=0 then ndays=dob_c1-'31DEC1999'd;
else if yea2=1 then ndays=dob_c1-'31DEC2000'd;
else if yea2=2 then ndays=dob_c1-'31DEC2001'd;
else if yea2=3 then ndays=dob_c1-'31DEC2002'd;
run;
data a;
set a;
allndays=dob_c1-'8APR1999'd;
run;
dob_c1的值是:01/01/2000, 01/02/2000，。。。。。。up to 12/31/2003
谢谢！ | a********s
发帖数: 188 | 2 You may first need to convert variables into Date types, and then use
similar code below to get new date.
x <- as.Date("31DEC2000", format = "%d%b%Y")
y <- as.Date("31DEC1999", format = "%d%b%Y")
diff <- x - y
new.dt <- y + as.difftime(diff, unit="days") | S********a
发帖数: 359 | 3 包子已经发了，谢谢回帖。
【在 a********s 的大作中提到】
: You may first need to convert variables into Date types, and then use
: similar code below to get new date.
: x <- as.Date("31DEC2000", format = "%d%b%Y")
: y <- as.Date("31DEC1999", format = "%d%b%Y")
: diff <- x - y
: new.dt <- y + as.difftime(diff, unit="days")
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