[R] read.table, write.table, logicals and spaces?
Michael A. Miller
mmiller3 at iupui.edu
Fri Nov 22 23:14:10 CET 2002
I have some data frames that contain logical values. When I
write the frame to a file with write.table(df, filename,
row.names=F, sep=','), I end up with the logicals looking like
either ...,FALSE,... or ..., TRUE,... . That space in front of
the TRUE is causing me problems when I read the frame again with
df <- read.table(filename,header=T,sep=',').
Reading the data leaves me with this:
> df$valid
[1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
[13] TRUE FALSE FALSE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE
[25] TRUE TRUE TRUE TRUE TRUE TRUE
Levels: TRUE FALSE
> as.logical(df$valid)
[1] NA NA NA NA NA NA NA NA NA NA NA NA
[13] NA FALSE FALSE NA NA NA FALSE NA NA NA NA NA
[25] NA NA NA NA NA NA
> as.character(df$valid)
[1] " TRUE" " TRUE" " TRUE" " TRUE" " TRUE" " TRUE" " TRUE" " TRUE" " TRUE"
[10] " TRUE" " TRUE" " TRUE" " TRUE" "FALSE" "FALSE" " TRUE" " TRUE" " TRUE"
[19] "FALSE" " TRUE" " TRUE" " TRUE" " TRUE" " TRUE" " TRUE" " TRUE" " TRUE"
[28] " TRUE" " TRUE" " TRUE"
Can anyone suggest a way to read this column so that I can use it
as a logical without having to first do something like
df$valid <- as.logical(sub(' ','',as.character(df$valid)))
Mike
--
Michael A. Miller mmiller3 at iupui.edu
Imaging Sciences, Department of Radiology, IU School of Medicine
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