Re: [R] Clever way to match two lists

Jim, That's perfect. Thanks. Also tried Neal's method, but it wound up be MUCH slower to build the index. Thanks, -- Noah Silverman, M.S. UCLA Department of Statistics 8117 Math Sciences Building Los Angeles, CA 90095 On Mar 21, 2013, at 6:07 PM, Jim Holtman wrote: > indx <- match(main.df

Re: [R] Clever way to match two lists

indx <- match(main.df$id, key$id, nomatch = 0) main.df$value[indx != 0] <- key$value[indx] Sent from my iPad On Mar 21, 2013, at 20:57, Noah Silverman wrote: > Hello, > > I have a large data.frame of 80,000 rows where each row is a record. Each > record is indexed by a unique ID in the first

[R] Clever way to match two lists

Hello, I have a large data.frame of 80,000 rows where each row is a record. Each record is indexed by a unique ID in the first column. I need to update values for a column for *some* of the records. I was given a data.frame with about 10,000 rows and two columns. The first is the record ID,