[R] Changing content of column in data.frame + efficient join extraction between 2 data.frames
Dear R users, I have 2 SpatialPointsDataFrame's, pcs and East. The column str_1 in the first (pcs) is: pcs[0:4,] coordinates cat str_1 int_1 int_2dbl_1 dbl_2 1 (101000, 263000) 1 SM06B 101000 263000 4.978915 -4.293668 2 (101000, 265000) 2 SM06C 101000 265000 4.960478 -4.266742 3 (101000, 267000) 3 SM06D 101000 267000 4.912984 -4.246849 4 (101000, 269000) 4 SM06E 101000 269000 4.613309 -4.185405 The column str_1 in the second (East) is: East[0:4,] coordinates str_1 1 (489000, 215000) sp81x 2 (489000, 217000) sp81y 3 (493000, 209000) sp90j 4 (495000, 209000) sp90p I would like to do 2 things: 1) I would like to change the format of the column str_1 in the first to be the same that it is in the second, that is I need to remove the inverted commas and I need to make it lower case. 2) I would like to extract the rows from the first one (pcs) where pcs$str_1 is the same as East$str_1. I have even tried regexp, but cannot modify the content of pcs$str_1 to remove the inveretd commas and change the case to lowercase. How do I do that? Regards -- Corrado Topi PhD Researcher Global Climate Change and Biodiversity Area 18,Department of Biology University of York, York, YO10 5YW, UK Phone: + 44 (0) 1904 328645, E-mail: ct...@york.ac.uk __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Changing content of column in data.frame + efficient join extraction between 2 data.frames
On Tue, 2010-03-23 at 09:37 +, Corrado wrote: Dear R users, I have 2 SpatialPointsDataFrame's, pcs and East. The column str_1 in the first (pcs) is: pcs[0:4,] coordinates cat str_1 int_1 int_2dbl_1 dbl_2 1 (101000, 263000) 1 SM06B 101000 263000 4.978915 -4.293668 2 (101000, 265000) 2 SM06C 101000 265000 4.960478 -4.266742 3 (101000, 267000) 3 SM06D 101000 267000 4.912984 -4.246849 4 (101000, 269000) 4 SM06E 101000 269000 4.613309 -4.185405 The column str_1 in the second (East) is: East[0:4,] coordinates str_1 1 (489000, 215000) sp81x 2 (489000, 217000) sp81y 3 (493000, 209000) sp90j 4 (495000, 209000) sp90p I would like to do 2 things: 1) I would like to change the format of the column str_1 in the first to be the same that it is in the second, that is I need to remove the inverted commas and I need to make it lower case. 2) I would like to extract the rows from the first one (pcs) where pcs$str_1 is the same as East$str_1. I have even tried regexp, but cannot modify the content of pcs$str_1 to remove the inveretd commas and change the case to lowercase. How do I do that? Regards Hi Corrado! First: tolower(pcs$str_1) change to lower case Second: try merge (East,pcs,by.x=str_1,by.y=str_1) to fusion data frames Third: I don't recreate your database East in my computer do you give a small part to I try solve your problem? -- Bernardo Rangel Tura, M.D,MPH,Ph.D National Institute of Cardiology Brazil __ R-help@r-project.org 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.