[Rd] delete.response leaves response in attribute dataClasses

From: Paul Johnson <pauljohn32_at_gmail.com>
Date: Thu, 05 Jan 2012 14:26:45 -0600


I posted this one as an R bug
(https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=14767), but Prof. Ripley says I'm premature, and I should raise the question here.

Here's the behavior I assert is a bug:
The output from delete.response on a terms object alters the formula by removing the dependent variable. It removes the response from the "variables" attribute and it changes the response attribute from 1 to 0. The response is removed from "predvars"

But it leaves the name of the dependent variable first in the in "dataClasses". It caused an unexpected behavior in my code, so (as usual) the bug may be mine, but in my heart, I believe it belongs to delete.response.

To illustrate, here's a terms object from a regression.

> tt
y ~ x1 * x2 + x3 + x4

attr(,"variables")
list(y, x1, x2, x3, x4)
attr(,"factors")
   x1 x2 x3 x4 x1:x2
y   0  0  0  0     0
x1  1  0  0  0     1
x2  0  1  0  0     1
x3  0  0  1  0     0
x4  0  0  0  1     0

attr(,"term.labels")
[1] "x1" "x2" "x3" "x4" "x1:x2"
attr(,"order")
[1] 1 1 1 1 2

attr(,"intercept")
[1] 1

attr(,"response")
[1] 1

attr(,".Environment")
<environment: R_GlobalEnv>
attr(,"predvars")
list(y, x1, x2, x3, x4)
attr(,"dataClasses")
        y        x1        x2        x3        x4
"numeric" "numeric" "numeric" "numeric" "numeric"

Now observe that delete.response removes the response from all attributes except dataClasses.

> delete.response(tt)
~x1 * x2 + x3 + x4

attr(,"variables")
list(x1, x2, x3, x4)
attr(,"factors")
   x1 x2 x3 x4 x1:x2
x1  1  0  0  0     1
x2  0  1  0  0     1
x3  0  0  1  0     0
x4  0  0  0  1     0

attr(,"term.labels")
[1] "x1" "x2" "x3" "x4" "x1:x2"
attr(,"order")
[1] 1 1 1 1 2

attr(,"intercept")
[1] 1

attr(,"response")
[1] 0

attr(,".Environment")
<environment: R_GlobalEnv>
attr(,"predvars")
list(x1, x2, x3, x4)
attr(,"dataClasses")
        y        x1        x2        x3        x4
"numeric" "numeric" "numeric" "numeric" "numeric"

pj

-- 
Paul E. Johnson
Professor, Political Science
1541 Lilac Lane, Room 504
University of Kansas

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Received on Thu 05 Jan 2012 - 20:30:27 GMT

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