Quick and simple (to ask). I'm using the latest version of R an RStudio on my Mac.
The first lm()
works, the second doesn't. The documentation for both functions is kind of spread out, so I can't trace a problem -- especially since R does not give me an error message. It quietly does whatever it's doing and the second fit isn't created.
theURL <- "http://lib.stat.cmu.edu/datasets/Andrews/T30.1"
theNames <- c("Table", "Number", "Row", "Experiment", "Temperature", "Concentration", "Time", "Unchanged", "Converted", "Unwanted")
Reaction <- read.table(theURL, header = F , col.names = theNames)
Reaction <- Reaction[-c(1:4)]
fitWorking <-lm(Converted~Temperature, data=Reaction)
with(Reaction,
fitBroken <- lm(Converted ~ Temperature)
)
Created on 2019-02-28 by the reprex package (v0.2.1)
For completeness, this is data table 30.1 from Andrews & Herzberg Data book.
You are leaving the output on a different environment (inside with statement) try this
theURL <- "http://lib.stat.cmu.edu/datasets/Andrews/T30.1"
theNames <- c("Table", "Number", "Row", "Experiment", "Temperature", "Concentration", "Time", "Unchanged", "Converted", "Unwanted")
Reaction <- read.table(theURL, header = F , col.names = theNames)
Reaction <- Reaction[-c(1:4)]
fitBroken <- with(Reaction, lm(Converted ~ Temperature))
fitBroken
#>
#> Call:
#> lm(formula = Converted ~ Temperature)
#>
#> Coefficients:
#> (Intercept) Temperature
#> 5.0731 0.3064
Created on 2019-03-01 by the reprex package (v0.2.1)
1 Like
You need to use <<-
for the assignment to escape the "with
" evaluation environment.
But I would say: in general consider not using with()
with lm()
. Organizing your code to use the data=
argument is a good idea.
lm(mpg ~ cyl, data = mtcars)
#>
#> Call:
#> lm(formula = mpg ~ cyl, data = mtcars)
#>
#> Coefficients:
#> (Intercept) cyl
#> 37.885 -2.876
with(mtcars, fit <<- lm(mpg ~ cyl))
fit
#>
#> Call:
#> lm(formula = mpg ~ cyl)
#>
#> Coefficients:
#> (Intercept) cyl
#> 37.885 -2.876
Created on 2019-02-28 by the reprex package (v0.2.1)
3 Likes
Drat! And I knew the answer, having written a warning to that effect one chapter ago.
system
Closed
March 22, 2019, 1:31am
5
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