Hello, I have question about referencing a variable that I created in a dataframe, and I am hoping the experts on here can be of assistance. I have a dataset of highway bridges with approximately 10,000 observations. I imported these into R in the form of a dataframe called "Bridges".
I am interested in running some basic linear models on a few key variables with the data. Say "CONDITION" is my dependent variable, and "TRAFFIC" and "WEATHER" are the independent variables I am considering. In order to capture a possible exponential relationship between "CONDITION", "TRAFFIC", and "WEATHER", I created the variable "LOG_COND": Bridges$LOG_COND = log(Bridges$CONDITION, base = exp(1)) I then used the "str" command to verify that the variable shows up correctly, and is of the correct form (numeric) in the dataframe. However, when I then attempt to use my new variable, say, for example: lm.bridges = lm(LOG_COND ~ TRAFFIC + WEATHER, data = Bridges), (not sure why the tilde symbol shows up as a minus sign here) I get "Error in eval(expr, envir, enclos) : object 'LOG_COND' not found" Can anyone enlighten me as to what I am doing wrong, and if possible, some basic code that I can use to rectify the situation? I am a pretty basic R user right now, so I'm definitely looking for something that is more functional than elegant. Thanks, -Steve -- View this message in context: http://r.789695.n4.nabble.com/Unable-to-reference-variable-created-in-dataframe-tp4640822.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
