# [Rd] Problem in step() and stepAIC() when a name of a regressors has b (PR#3991)

Andrea.Capodicasa at albacom.it Andrea.Capodicasa at albacom.it
Wed Aug 27 11:39:29 MEST 2003

```Hi all,
I've experienced this problem using step() and stepAIC() when a name of a
regressors has blanks in between (R:R1.7.0, os: w2ksp4).

Please look at the following code:

"x" <-
c(14.122739306734, 14.4831100207131, 14.5556459667089,
14.5777151911177,
14.5285815352327, 14.0217803203846, 14.0732571632964,
14.7801310180502,
14.7839362960477, 14.7862217992577)

"reg" <-
structure(list(feriale = c(0, 1, 1, 1, 1, 0, 0, 1, 1, 1),
pasquetta = c(0,
0, 0, 0, 0, 0, 0, 0, 0, 0), giorno = structure(c(2, 3, 4, 5,

6, 7, 1, 2, 3, 4), class = "factor", .Label = c("1-DOM",
"2-LUN",
"3-MAR", "4-MER", "5-GIO", "6-VEN", "7-SAB"))), .Names =
c("feriale",
"pasquetta", "giorno"), row.names = c("1", "2", "3", "4",
"5",
"6", "7", "8", "9", "10"), class = "data.frame")

#this works
lm(x~., data=reg)

#this works
step(lm(x~., data=reg))

#this works
library(MASS)
stepAIC(lm(x~., data=reg))

#when you change a name of a regressors inserting blanks
step and stepAIC won't work
names(reg)[1]="with blank"
names(reg)

#this still works
lm(x~., data=reg)

#this doesn't work
step(lm(x~., data=reg))

#this is the error
#"Error in parse(file, n, text, prompt) : parse error"

#this doesn't work
stepAIC(lm(x~., data=reg))

# the error is the same as step
#"Error in parse(file, n, text, prompt) : parse error"

These are my R.version() and Sys.info() relevant infos.
> R.Version()
\$platform
[1] "i386-pc-mingw32"

\$arch
[1] "i386"

\$os
[1] "mingw32"

\$system
[1] "i386, mingw32"

\$status
[1] ""

\$major
[1] "1"

\$minor
[1] "7.0"

\$year
[1] "2003"

\$month
[1] "04"

\$day
[1] "16"

\$language
[1] "R"

> Sys.info()
sysname                       release
version
"Windows"                      "NT 5.0" "(build 2195)
Service Pack 4"
machine
"x86"

```