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if (.R.) {
stata.get <- function(file, lowernames=FALSE,
convert.dates=TRUE, convert.factors=TRUE,
missing.type=FALSE, convert.underscore=TRUE,
warn.missing.labels=TRUE, force.single=TRUE,
allow=NULL, charfactor=FALSE, ...)
{
## depends on the read.dta function from foriegn
require('foreign')
## Function to convert the elements of w into more compact
## data storage types.
convertObjs <- function(x, charfactor, force.single) {
## Date is not nessarely a integer but it ignores any
## fraction it might have
if((inherits(x, 'Date') || is.factor(x))
&& storage.mode(x) != 'integer') {
storage.mode(x) <- 'integer'
} else if(charfactor && is.character(x)) {
## If x is a character and arg charfactor is TRUE then
## convert x to a factor if there are more than 2 letters in
## any element && the number of unique values of x is less then
## half the total number of values in x
if(max(nchar(x)) >= 2 && (length(unique(x)) < length(x) / 2)) {
x <- factor(x)
}
} else if(is.numeric(x)) {
if(all(is.na(x))) {
## if all values are NA then convert to integer because
## it is 4 bytes instead of 8
storage.mode(x) <- 'integer'
}
else if(force.single && max(abs(x), na.rm=TRUE) <= (2^31-1) &&
all(floor(x) == x, na.rm=TRUE)) {
## convert x to integer if arg force.single is TRUE and the maximum
## absolute value of x is less then maximum value that an integer
## can store.
storage.mode(x) <- 'integer'
}
}
return(x)
}
## A function to create additional attributes to add to the elements of
## w
create.attribs <- function(var.label, val.label, format, label.table) {
attribs <- list()
if(format != '') {
attribs$format <- format
}
## Translate var labels into Hmisc var lables
if(var.label != '') {
attribs$label <- var.label
}
## The label.table values are found by looking a the checking to see
## if there is a non-empty value in val.labels. That value corrasponds
## a named element in label.table.
## Check to see if val.label is not empty and it is one of the
## names in label.table and that its value is not NULL
if(val.label != '' && val.label %in% names(label.table) &&
!is.null(label.table[[val.label]])) {
attribs$value.label.table <- label.table[[val.label]]
}
return(attribs)
}
## If file is a url download and set file = to temp file name
if(length(grep('^http://', file))){
tf <- tempfile()
download.file(file, tf, mode='wb', quiet=TRUE)
file <- tf
}
## Read the stata file into w
w <- read.dta(file, convert.dates=convert.dates,
convert.factors=convert.factors,
missing.type=missing.type,
convert.underscore=convert.underscore,
warn.missing.labels=warn.missing.labels, ...)
## extract attributes from w
a <- attributes(w)
num.vars <- length(w)
## Do translate attributes names into R names
nam <- makeNames(a$names, unique=TRUE, allow=allow)
if(lowernames) nam <- casefold(nam, upper=FALSE)
a$names <- nam
## If var.labels is empty then create a empty char vector.
if(!length(a$var.labels)) {
a$var.labels <- character(num.vars)
}
## If val.labels is empty then create an empty char vector.
if(length(a$val.labels)) {
val.labels <- a$val.labels
} else {
val.labels <- character(num.vars)
}
## create list of attributes for the elements in w. An mapply is faster
## then a for loop in large data sets.
attribs <- mapply(FUN=create.attribs, var.label=a$var.labels,
val.label=val.labels, format=a$formats,
MoreArgs=list(label.table=a$label.table),
SIMPLIFY=FALSE)
## clear var.labels attribute
attr(w, 'var.labels') <- NULL
## Convert the elements of w as needed
w <- lapply(w, FUN=convertObjs, force.single=force.single,
charfactor=charfactor)
## strip off the naming info for w
w <- unname(w)
## add the new attributes to the current attributes of
## the elements of w
for(i in seq(along.with=w)) {
## Set the label for the element
if('label' %in% names(attribs[[i]])) {
label(w[[i]]) <- attribs[[i]]$label
## clear the label value from attribs[[i]]
attribs[[i]]$label <- NULL
}
## combine the new attribs with the current attributes
combine(attributes(w[[i]])) <- attribs[[i]]
}
## add the names, rownames, class variables, and some extra stata
## info back to w
stata.info <- a[c('datalabel','version','time.stamp','val.labels','label.table')]
attributes(w) <- c(a[c('names','row.names','class')],
stata.info=list(stata.info))
return(w)
}
NULL
}
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