Entering edit mode
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Subset replacement like this
df['a','c2']<-3
depends on the position of row 'a' when 'c2' is a new column.
Row 'a' first:
> df1 <- DataFrame(c1=1:2,row.names=c("a","b"))
> df1['a','c2'] <- 3
> df1
DataFrame with 2 rows and 2 columns
c1 c2
<integer> <numeric>
a 1 3
b 2 3
Row 'a' second:
> df2 <- DataFrame(c1=1:2,row.names= rev( c("a","b") ))
> df2['a','c2'] <- 3
> df2
DataFrame with 2 rows and 2 columns
c1 c2
<integer> <numeric>
b 1 NA
a 2 3
FWIW, the latter - but not the former - agrees with "the 'DataFrame'
behaves
very similarly to 'data.frame'"(from the help page).
> sessionInfo()
R version 2.15.2 (2012-10-26)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] IRanges_1.16.4 BiocGenerics_0.4.0
loaded via a namespace (and not attached):
[1] parallel_2.15.2 stats4_2.15.2