Re: [R] assign multiple variables at once

Brian Diggs Fri, 13 Aug 2010 13:12:35 -0700

On 8/13/2010 11:08 AM, Hosack, Michael wrote:

R Experts,


I would like to create a series of variables without having
to assign a separate line of code for each new variable. My dataframe (DF) 
contains
two groups of linked variables (ESP1:ESP9) and (ECRL1:ECRL9). Within ESP1:ESP9 
are
abbreviated species codes (full dataframe contains 26 codes). ECRL1 represents 
the
number of species x in variable ESP1 harvested, and so on through ESP9 and 
ECRL9.
What I want to do is create 26 new variables (one for each unique species code) 
that
contains the number harvested (ECRL) for each corresponding species code listed 
for
each row of the data set. Example (row 14), the new variable YP Harvest would 
equal
90 (ECRL2) and WP Harvest would equal 0 (ECRL1), all other species code var's 
would
contain NA.

I hope I made this clear enough.

Thank you,

Mike

Current method: one line per species

EBTCH1.h$YP.H<- with(EBTCH1.h,ifelse(ESP1 %in% 'YP',ECRL1,ifelse(ESP2 %in% 
'YP',ECRL2,
ifelse(ESP3 %in% 'YP',ECRL3,ifelse(ESP4 %in% 'YP',ECRL4,ifelse(ESP5 %in% 
'YP',ECRL5,
ifelse(ESP6 %in% 'YP',ECRL6,ifelse(ESP7 %in% 'YP',ECRL7,ifelse(ESP8 %in% 
'YP',ECRL8,
ifelse(ESP9 %in% 'YP',ECRL9,0))))))))))


DF<-
structure(list(MM = c(5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L,
5L, 5L, 5L, 5L, 5L), DD = c(3L, 3L, 3L, 3L, 3L, 3L, 7L, 7L, 7L,
8L, 8L, 8L, 8L, 8L, 8L), DTYPE = c(2, 2, 2, 2, 2, 2, 1, 1, 1,
1, 1, 1, 1, 1, 1), TOD = c(2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1,
1, 1, 1), SITENUM = c("102", "104", "104", "104", "101", "101",
"102", "103", "101", "101", "101", "101", "103", "103", "103"
), CURTIM = c(1450L, 1736L, 1755L, 1804L, 1950L, 2007L, 1150L,
1450L, 2000L, 1003L, 1030L, 1036L, 1300L, 1310L, 1320L), GRPFSH = c(2L,
2L, 2L, 2L, 2L, 3L, 1L, 2L, 3L, 2L, 4L, 1L, 1L, 3L, 1L), EEFF = c(11.5,
19, 5, 20, 0, 0, 5, 8, 0, 0, 0, 0, 3, 12, 6), ESP1 = c("SMB",
"SMB", "SMB", "SMB", NA, NA, "YP", "YP", NA, NA, NA, NA, "RG",
"WP", "WP"), ESP2 = c(NA, "RB", NA, NA, NA, NA, NA, NA, NA, NA,
NA, NA, "SMB", "YP", "YP"), ESP3 = c(NA, NA, NA, NA, NA, NA,
NA, NA, NA, NA, NA, NA, "RB", "RBS", NA), ESP4 = c(NA_character_,
NA_character_, NA_character_, NA_character_, NA_character_, NA_character_,
NA_character_, NA_character_, NA_character_, NA_character_, NA_character_,
NA_character_, NA_character_, NA_character_, NA_character_),
     ESP5 = c(NA_character_, NA_character_, NA_character_, NA_character_,
     NA_character_, NA_character_, NA_character_, NA_character_,
     NA_character_, NA_character_, NA_character_, NA_character_,
     NA_character_, NA_character_, NA_character_), ESP6 = c(NA,
     NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA),
     ESP7 = c(NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
     NA, NA, NA), ESP8 = c(NA, NA, NA, NA, NA, NA, NA, NA, NA,
     NA, NA, NA, NA, NA, NA), ESP9 = c(NA, NA, NA, NA, NA, NA,
     NA, NA, NA, NA, NA, NA, NA, NA, NA), ECRL1 = c(0L, 0L, 0L,
     0L, 0L, 0L, 4L, 5L, 0L, 0L, 0L, 0L, 0L, 0L, 0L), ECRL2 = c(0L,
     0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 90L, 30L),
     ECRL3 = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
     0L, 0L, 0L), ECRL4 = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
     0L, 0L, 0L, 0L, 0L, 0L), ECRL5 = c(0L, 0L, 0L, 0L, 0L, 0L,
     0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L), ECRL6 = c(0L, 0L, 0L,
     0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L), ECRL7 = c(0L,
     0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L),
     ECRL8 = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
     0L, 0L, 0L), ECRL9 = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
     0L, 0L, 0L, 0L, 0L, 0L)), .Names = c("MM", "DD", "DTYPE",
"TOD", "SITENUM", "CURTIM", "GRPFSH", "EEFF", "ESP1", "ESP2",
"ESP3", "ESP4", "ESP5", "ESP6", "ESP7", "ESP8", "ESP9", "ECRL1",
"ECRL2", "ECRL3", "ECRL4", "ECRL5", "ECRL6", "ECRL7", "ECRL8",
"ECRL9"), row.names = c(NA, 15L), class = "data.frame")


Michael,

An easier approach is to reshape this into a long format (one row foreach ESP/ECRL combination, carrying the rest of the identifyingvariables), and then reshape it back to wide format using the ESP valueto define the new column:


# for convenience, variables that don't vary for each observation
idvar <- names(DF)[1:8]

DFr <- reshape(DF,varying=list(c("ESP1","ESP2","ESP3","ESP4","ESP5","ESP6","ESP7","ESP8","ESP9"),c("ECRL1","ECRL2","ECRL3","ECRL4","ECRL5","ECRL6","ECRL7","ECRL8","ECRL9")),timevar=NULL, idvar=idvar, direction="long", v.name=c("ESP","ECRL"))


DFr <- DFr[!is.na(DFr$ESP),]

DFr <- reshape(DFr, timevar="ESP", idvar=idvar, direction="wide")

merge(DF, DFr, by=idvar)

If you want to rename columns, or convert NA's to 0, you can do that toDFr or after the merge.


--
Brian Diggs

Senior Research Associate, Department of Surgery, Oregon Health &Science University


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Re: [R] assign multiple variables at once

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