Dear expeRts, I have some programming questions about NULL in R.There are listed as follows: 1. I find i can't let a list have a element NULL: a<-list() a$ress<-1 a$res<-NULL a str(a)
How can i know i have a named element but it is NULL, not just get a$xxxx,a$iiii,a$oooo there all get NULL 2.The most important thing: a<-1:10 b<-NULL or 1 a<-c(a,b) will work so i don't need to know whether b is null or not,but: a[-NULL] can't work!! i just need a[-NULL]==a , how can i reach this purpose? -- PO SU mail: [email protected] Majored in Statistics from SJTU ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
