This is another approach using match(): df1 = data.frame(x1 = letters[1:26],x2 = NA, stringsAsFactors=FALSE) df2 = data.frame(x1 = letters[10:15],x2 = c("1a","2a","3a","4a","5a","6a"), stringsAsFactors =FALSE)
df1$x2[match(df2$x1, df1$x1)] <- df2$x2 --------------------------------------------- David L. Carlson Department of Anthropology Texas A&M University -----Original Message----- From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Eric Berger Sent: Friday, February 15, 2019 11:43 PM To: javad bayat <j.bayat...@gmail.com> Cc: R mailing list <R-help@r-project.org>; r-help-ow...@r-project.org Subject: Re: [R] Problem with combining 2 data frame Hi Javad, You have a number of problems with your code, such as: 1. you should set df1 and df2 without factors 2. you define a function f(x,y) but the body of the function never refers to x and y The following code does what I think you are looking for: df1 = data.frame(x1 = letters[1:26],x2 = NA,stringsAsFactors = FALSE) df2 = data.frame(x1 = letters[10:15],x2 = c("1a","2a","3a","4a","5a","6a"), stringsAsFactors = FALSE) aa <- sapply( 1:nrow(df2), function(i) { df1$x2[ df1$x1==df2$x1[i] ] <<- df2$x2[i] } ) HTH, Eric On Sat, Feb 16, 2019 at 4:11 AM javad bayat <j.bayat...@gmail.com> wrote: > Dear R users; > I am trying to combine 2 dataframes with different rows, 26 and 6 rows. The > first column of both dataframe has something in common, and I want to > compare the first column of the df1 with first column of the df2 to see if > they are same or not. Then if they were same, the second column of the df1 > fill by the value of the second column of df2. > > df1 = data.frame(x1 = letters[1:26],x2 = NA) > df2 = data.frame(x1 = letters[10:15],x2 = c("1a","2a","3a","4a","5a","6a")) > > f = function(x,y){ > for (i in 1:nrow(df1)) > ifelse(df1$x1 == df2$x1, df1$x2==df2$x2, "NA")} > f(df1,df2) > Error in Ops.factor(df1$x1, df2$x1) : level sets of factors are different > > Is there anyone to help me to solve this problem? > Sincerely. > > > > > > > > > > > -- > Best Regards > Javad Bayat > M.Sc. Environment Engineering > Alternative Mail: bayat...@yahoo.com > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.