[R] by can not find transpose function

[Sorkin, John]

I am trying to transpose a dataframe by its first column using the by statement using the t function. When I use the by function, I get a message,

Error in FUN(X[[i]], ...) : could not find function "FUN"

I don't think I have a syntax error in my by statement because the by statment works using the print function.

Data and an executable example follows:

phonydata2 <- structure(list(INTRVNTN = c("CONTROL", "CONTROL", "CONTROL",
"MPR+NMES+HPRO", "CONTROL", "CONTROL", "CONTROL", "CONTROL",
"MPR+NMES+HPRO", "MPR+NMES+HPRO", "CONTROL", "CONTROL", "CONTROL",
"MPR+NMES+HPRO", "MPR+NMES+HPRO", "MPR+NMES+HPRO", "CONTROL",
"MPR+NMES+HPRO", "MPR+NMES+HPRO", "CONTROL", "MPR+NMES+HPRO",
"CONTROL", "CONTROL", "MPR+NMES+HPRO", "CONTROL", "CONTROL",
"CONTROL", "MPR+NMES+HPRO", "CONTROL", "MPR+NMES+HPRO", "MPR+NMES+HPRO",
"MPR+NMES+HPRO"), HGDOM1_MW1 = c(NA, NA, NA, NA, NA, NA, 17,
30, 27.5, 12, 16, 16, 14, NA, 33, NA, 12, 25, NA, NA, 6, NA,
13.5, 10, 1, NA, 12, 18, NA, NA, NA, NA), HGDOM1_W1 = c(8, NA,
NA, 4, NA, NA, 18, NA, 26.5, 22, 14, 8, NA, NA, 33, NA, 15, NA,
4, 9, 18, NA, 14, 16, 2, NA, 18, 15, NA, NA, NA, NA)), .Names = c("INTRVNTN",
"HGDOM1_MW1", "HGDOM1_W1"), class = "data.frame", row.names = c(NA,
-32L))

phonydata2

# This works
by(phonydata2[,2:3],phonydata2[,1],print)
# This gives and error message.
by(phonydata2[,2:3],phonydata2[,1],t)

Thank you,
John








John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing)


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