Hi, I have two columns that contain numbers along with letters (as shown below) and have different lengths. Each entry in the first column is likely to be found in the second column at most once. For each entry of the first column, if that entry is found in the second column, I would like to get the corresponding index. For instance, if the first entry of the first column is 5th entry in the second column, I would like to keep this index 5. AST2017000005534 TUR2017000001428 CTS2017000079930 CTS2017000071989 CTS2017000079931 CTS2017000072015 In a loop, when I use the following code to get those indices, data_2 = read.csv("excel_data.csv") column_1 = data_2$data1 column_2 = data_2$data2 match_list <- array(0,dim=c(310,1)); # 310 is the length of the first column for (indx in 1: 310){ for(indx2 in 1:713){ # 713 is the length of the second column if(column_1[indx] == column_2[indx2] ){ match_list[indx,1] = indx2; break; } } } R provides the following error: Error in Ops.factor(column_1[indx], column_2[indx2]) : level sets of factors are different So can someone explain me how I can resolve this issue? Thnak you, Yasin [[alternative HTML version deleted]]

The error is because the read.csv function converted both columns to factors. The simplest thing to do is to set stringsAsFactors=FALSE is the call to read.csv so that they are compared as strings. You could also call as.character on each of the columns if you don't want to read the data in again. Also, look at the match function, I think it will give you what you want without the explicit looping. On Thu, Oct 12, 2017 at 2:25 PM, Yasin Gocgun <yasing053 at gmail.com> wrote:> Hi, > > I have two columns that contain numbers along with letters (as shown below) > and have different lengths. Each entry in the first column is likely to be > found in the second column at most once. > > For each entry of the first column, if that entry is found in the second > column, I would like to get the corresponding index. For instance, if the > first entry of the first column is 5th entry in the second column, I would > like to keep this index 5. > > AST2017000005534 TUR2017000001428 > CTS2017000079930 CTS2017000071989 > CTS2017000079931 CTS2017000072015 > > In a loop, when I use the following code to get those indices, > > > data_2 = read.csv("excel_data.csv") > column_1 = data_2$data1 > column_2 = data_2$data2 > > match_list <- array(0,dim=c(310,1)); # 310 is the length of the first > column > > for (indx in 1: 310){ > for(indx2 in 1:713){ # 713 is the length of the second column > if(column_1[indx] == column_2[indx2] ){ > match_list[indx,1] = indx2; > break; > } > } > } > > > R provides the following error: > > Error in Ops.factor(column_1[indx], column_2[indx2]) : > level sets of factors are different > > So can someone explain me how I can resolve this issue? > > Thnak you, > > Yasin > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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.-- Gregory (Greg) L. Snow Ph.D. 538280 at gmail.com

It's generally a very good idea to examine the structure of data after you have read it in. str(data2) would have shown you that read.csv() turned your strings into factors, and that's why the == operator no longer does what you think it does. use ... data_2 <- read.csv("excel_data.csv", stringsAsFactors = FALSE) ... to turn this off. Also, the %in% operator will achieve more directly what you are trying to do. No need for loops. B.> On Oct 12, 2017, at 4:25 PM, Yasin Gocgun <yasing053 at gmail.com> wrote: > > Hi, > > I have two columns that contain numbers along with letters (as shown below) > and have different lengths. Each entry in the first column is likely to be > found in the second column at most once. > > For each entry of the first column, if that entry is found in the second > column, I would like to get the corresponding index. For instance, if the > first entry of the first column is 5th entry in the second column, I would > like to keep this index 5. > > AST2017000005534 TUR2017000001428 > CTS2017000079930 CTS2017000071989 > CTS2017000079931 CTS2017000072015 > > In a loop, when I use the following code to get those indices, > > > data_2 = read.csv("excel_data.csv") > column_1 = data_2$data1 > column_2 = data_2$data2 > > match_list <- array(0,dim=c(310,1)); # 310 is the length of the first > column > > for (indx in 1: 310){ > for(indx2 in 1:713){ # 713 is the length of the second column > if(column_1[indx] == column_2[indx2] ){ > match_list[indx,1] = indx2; > break; > } > } > } > > > R provides the following error: > > Error in Ops.factor(column_1[indx], column_2[indx2]) : > level sets of factors are different > > So can someone explain me how I can resolve this issue? > > Thnak you, > > Yasin > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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.

data_2 <- read.csv("excel_data.csv",stringsAsFactors=FALSE) column_1 <- data_2$data1 column_2 <- data_2$data2 result <- match( column_1, column_2 ) Please read the Posting Guide mentioned at the bottom of this and every posting, in particular about posting plain text so that what we see will be what you saw when you sent the message. You should also read about how to create reproducible examples, e.g. about using dput as mentioned in [1] and [2], and verifying the example before sending it [3]. [1] http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example [2] http://adv-r.had.co.nz/Reproducibility.html [3] https://cran.r-project.org/web/packages/reprex/index.html (read the vignette) -- Sent from my phone. Please excuse my brevity. On October 12, 2017 9:25:35 PM GMT+01:00, Yasin Gocgun <yasing053 at gmail.com> wrote:>Hi, > >I have two columns that contain numbers along with letters (as shown >below) >and have different lengths. Each entry in the first column is likely to >be > found in the second column at most once. > >For each entry of the first column, if that entry is found in the >second >column, I would like to get the corresponding index. For instance, if >the >first entry of the first column is 5th entry in the second column, I >would >like to keep this index 5. > >AST2017000005534 TUR2017000001428 >CTS2017000079930 CTS2017000071989 >CTS2017000079931 CTS2017000072015 > >In a loop, when I use the following code to get those indices, > > >data_2 = read.csv("excel_data.csv") >column_1 = data_2$data1 >column_2 = data_2$data2 > >match_list <- array(0,dim=c(310,1)); # 310 is the length of the first >column > >for (indx in 1: 310){ > for(indx2 in 1:713){ # 713 is the length of the second column > if(column_1[indx] == column_2[indx2] ){ > match_list[indx,1] = indx2; > break; > } > } >} > > >R provides the following error: > >Error in Ops.factor(column_1[indx], column_2[indx2]) : > level sets of factors are different > >So can someone explain me how I can resolve this issue? > >Thnak you, > >Yasin > > [[alternative HTML version deleted]] > >______________________________________________ >R-help at 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.