From amaliy1 at uic.edu  Tue Sep  5 03:40:02 2006
From: amaliy1 at uic.edu (amaliy1 at uic.edu)
Date: Tue,  5 Sep 2006 03:40:02 +0200 (CEST)
Subject: [Rd] Bugs with partial name matching during partial replacement
	(PR#9202)
Message-ID: <20060905014002.634C928F8E@slim.kubism.ku.dk>

Hello,

First the version info:
platform       powerpc-apple-darwin8.6.0
arch           powerpc
os             darwin8.6.0
system         powerpc, darwin8.6.0
status
major          2
minor          3.1
year           2006
month          06
day            01
svn rev        38247
language       R
version.string Version 2.3.1 (2006-06-01)

I have encountered some unusual behavior when trying to create new  
columns in a data frame that have names that would generate a partial  
match with an existing column with a longer name.  It is my  
understanding that replacement operations shouldn't have partial  
matching, but it is not clear to me whether this applies only when  
the named column exists and not for new assignments.

The first example:

 > D = data.frame(M=c(T,T,F,F,F,T,F,T,F,F,T,T,T),V=I(sprintf("ZZ%02d", 
1:13)),ABCD=13:1)
 > D
        M    V ABCD
1   TRUE ZZ01   13
2   TRUE ZZ02   12
3  FALSE ZZ03   11
4  FALSE ZZ04   10
5  FALSE ZZ05    9
6   TRUE ZZ06    8
7  FALSE ZZ07    7
8   TRUE ZZ08    6
9  FALSE ZZ09    5
10 FALSE ZZ10    4
11  TRUE ZZ11    3
12  TRUE ZZ12    2
13  TRUE ZZ13    1
 > D$CBA[D$M] = D$V[D$M]
 > D
        M    V ABCD  CBA
1   TRUE ZZ01   13 ZZ01
2   TRUE ZZ02   12 ZZ02
3  FALSE ZZ03   11 <NA>
4  FALSE ZZ04   10 <NA>
5  FALSE ZZ05    9 <NA>
6   TRUE ZZ06    8 ZZ06
7  FALSE ZZ07    7 <NA>
8   TRUE ZZ08    6 ZZ08
9  FALSE ZZ09    5 <NA>
10 FALSE ZZ10    4 <NA>
11  TRUE ZZ11    3 ZZ11
12  TRUE ZZ12    2 ZZ12
13  TRUE ZZ13    1 ZZ13
 > D$ABC[D$M] = D$V[D$M]
 > D
        M    V ABCD  CBA  ABC
1   TRUE ZZ01   13 ZZ01 ZZ01
2   TRUE ZZ02   12 ZZ02 ZZ02
3  FALSE ZZ03   11 <NA>   11
4  FALSE ZZ04   10 <NA>   10
5  FALSE ZZ05    9 <NA>    9
6   TRUE ZZ06    8 ZZ06 ZZ06
7  FALSE ZZ07    7 <NA>    7
8   TRUE ZZ08    6 ZZ08 ZZ08
9  FALSE ZZ09    5 <NA>    5
10 FALSE ZZ10    4 <NA>    4
11  TRUE ZZ11    3 ZZ11 ZZ11
12  TRUE ZZ12    2 ZZ12 ZZ12
13  TRUE ZZ13    1 ZZ13 ZZ13

I expected ABC to equal CBA with NA values in rows not assigned, but  
instead it appears that an extraction from D$ABCD and coercion to  
string is being performed in the process of creating D$ABC.

Here is something I believe is definitely a bug:

 > D = data.frame(M=c(T,T,F,F,F,T,F,T,F,F,T,T,T),V=1:13,ABCD=13:1)
 > D
        M  V ABCD
1   TRUE  1   13
2   TRUE  2   12
3  FALSE  3   11
4  FALSE  4   10
5  FALSE  5    9
6   TRUE  6    8
7  FALSE  7    7
8   TRUE  8    6
9  FALSE  9    5
10 FALSE 10    4
11  TRUE 11    3
12  TRUE 12    2
13  TRUE 13    1
 > D$CBA[D$M] = D$V[D$M]
 > D
        M  V ABCD CBA
1   TRUE  1   13   1
2   TRUE  2   12   2
3  FALSE  3   11  NA
4  FALSE  4   10  NA
5  FALSE  5    9  NA
6   TRUE  6    8   6
7  FALSE  7    7  NA
8   TRUE  8    6   8
9  FALSE  9    5  NA
10 FALSE 10    4  NA
11  TRUE 11    3  11
12  TRUE 12    2  12
13  TRUE 13    1  13
 > D$ABC[D$M] = D$V[D$M]
 > D
        M  V ABCD CBA ABC
1   TRUE  1    1   1   1
2   TRUE  2    2   2   2
3  FALSE  3   11  NA  11
4  FALSE  4   10  NA  10
5  FALSE  5    9  NA   9
6   TRUE  6    6   6   6
7  FALSE  7    7  NA   7
8   TRUE  8    8   8   8
9  FALSE  9    5  NA   5
10 FALSE 10    4  NA   4
11  TRUE 11   11  11  11
12  TRUE 12   12  12  12
13  TRUE 13   13  13  13

ABC is created as before with valued from ABCD in the unassigned  
rows, but ABCD is being modified as well.  The only difference form  
the previous example is that V is now just a numeric column.

Anil Maliyekkel




[Rd] Bugs with partial name matching during partial replacement (PR#9202)
amaliy1 at uic.edu