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trim =
function(x)
gsub("(^[[:space:]]+|[[:space:]]+$)", "", x)
textNodesOnly =
# Only process the top-level text nodes, not recursively.
# Could be done as simply as
# xmlValue(x, recursive = FALSE)
function(x)
paste(xmlSApply(x, function(n) if(is(n, "XMLInternalTextNode")) xmlValue(n) else ""), collapse = "")
toNumber =
function(x)
{
as.numeric(gsub("[%,]", "", x))
}
if(FALSE) {
doc = htmlParse("http://elections.nytimes.com/2008/results/states/president/california.html")
tbls = getNodeSet(doc, "//table[not(./tbody)]|//table/tbody")
o = readHTMLTable(tbls[[1]], skip.rows = c(1, Inf), header = FALSE, colClasses = c("character", replicate(5, toNumber)), elFun = textOnly)
o = readHTMLTable("http://elections.nytimes.com/2008/results/states/president/california.html")
x = readHTMLTable("http://www.usatoday.com/news/politicselections/vote2004/CA.htm", as.data.frame = FALSE)
}
setGeneric("readHTMLTable",
function(doc, header = NA,
colClasses = NULL, skip.rows = integer(), trim = TRUE, elFun = xmlValue,
as.data.frame = TRUE, which = integer(), ...)
standardGeneric("readHTMLTable"))
setMethod("readHTMLTable", "character",
function(doc, header = NA,
colClasses = NULL, skip.rows = integer(), trim = TRUE, elFun = xmlValue,
as.data.frame = TRUE, which = integer(), encoding = character(), ...) {
pdoc = htmlParse(doc, encoding = encoding)
readHTMLTable(pdoc, header, colClasses, skip.rows, trim, elFun, as.data.frame, which, ...)
})
# XXX Should vectorize in header, colClasses, i.e. allow different values for different tables.
setMethod("readHTMLTable", "HTMLInternalDocument",
function(doc, header = NA,
colClasses = NULL, skip.rows = integer(), trim = TRUE, elFun = xmlValue,
as.data.frame = TRUE, which = integer(), ...)
{
# tbls = getNodeSet(doc, "//table[not(./tbody)]|//table/tbody")
tbls = getNodeSet(doc, "//table") # XXX probably want something related to nested tables
# "//table[not(ancestor::table)]" -> outer ones
# if header is missing, compute it each time.
if(length(which))
tbls = tbls[which]
# ans = lapply(tbls, readHTMLTable, header, colClasses, skip.rows, trim, elFun, as.data.frame, ...)
header = rep(header, length = length(tbls))
ans = mapply(readHTMLTable,
tbls, header,
MoreArgs = list(colClasses = colClasses, skip.rows = skip.rows, trim = trim, elFun = elFun, as.data.frame = as.data.frame, ...),
SIMPLIFY = FALSE)
names(ans) = sapply(tbls, getHTMLTableName)
if(length(which) && length(tbls) == 1)
ans[[1]]
else
ans
})
getHTMLTableName =
function(node)
{
id = xmlGetAttr(node, "id")
if(!is.null(id))
return(id)
cap = getNodeSet(node, "./caption")
if(length(cap))
return(xmlValue(cap[[1]]))
}
setClass("FormattedNumber", contains = "numeric")
setClass("FormattedInteger", contains = "integer")
setAs('character', 'FormattedNumber', function(from) as.numeric(gsub(",", "", from)))
setAs('character', 'FormattedInteger', function(from) as.integer(gsub(",", "", from)))
setClass("Currency", contains = "numeric")
setAs("character", "Currency",
function(from)
as.numeric(gsub("[$,]", "", from)))
setClass("Percent", contains = "numeric")
setAs('character', 'Percent', function(from) as.numeric(gsub("%", "", from)))
setMethod("readHTMLTable", "XMLInternalElementNode",
#readHTMLTable.XMLInternalElementNode =
#
#
# header is computed based on whether we have a table node and it has a thead.
# (We don't currently bother with the col spans.)
#
# colClasses can be a character vector giving the name of the type for a column,
# an NULL to drop the corresponding column, or a function in which case it will
# be passed the contents of the column and can transform it as it wants.
# This allows us to clean text before converting it.
#
# skip.rows - an integer vector indicating which rows to ignore.
#
# trim - a logical indicating whether to trim white space from the start and end of text.
#
# elFun - a function which is called to process each th or td node to extract the content.
# This is typically xmlValue, but one can supply others (e.g. textNodesOnly)
# as.data.frame
#
function(doc, header = NA ,
colClasses = NULL, skip.rows = integer(), trim = TRUE, elFun = xmlValue,
as.data.frame = TRUE, encoding = 0L, ...)
{
node = doc
headerFromTable = FALSE
dropFirstRow = FALSE
# check if we have a header
if(length(header) == 1 && is.na(header)) # this node was doc
header = (xmlName(doc) %in% c("table", "tbody") &&
("thead" %in% names(doc) || length(getNodeSet(node, "./tr[1]/th | ./tr[1]/td")) > 0))
if(is.logical(header) && (is.na(header) || header) && xmlName(node) == "table") {
if("thead" %in% names(node))
header = node[["thead"]]
else {
if("tr" %in% names(node))
tmp = node[["tr"]]
else
tmp = node[["tbody"]][["tr"]]
if(!is.null(tmp) && all(names(tmp) %in% c('text', 'th'))) {
header = xpathSApply(tmp, "./th | ./td", xmlValue, encoding = encoding)
dropFirstRow = TRUE
}
}
}
# Moved this from before the check for header as we set node here and that seems
# premature. Checked on
# readHTMLTable("http://www.google.com/finance?q=NASDAQ:MSFT&fstype=ii", header = TRUE, which = 1)
tbody = getNodeSet(node, "./tbody")
if(length(tbody))
node = tbody[[1]]
if(is(header, "XMLInternalElementNode")) {
# get the last tr in the thead
if(xmlName(header) == "thead") {
i = which(names(header) == "tr")
header = header[[ i [ length(i) ] ]]
xpath = "./th | ./td"
} else
xpath = "./*/th | ./*/td"
header = as.character(xpathSApply(header, xpath, elFun, encoding = encoding))
headerFromTable = TRUE
if(xmlName(node) == "table" && "tbody" %in% names(node))
node = node[["tbody"]]
}
# Process each row, by getting the content of each "cell" (th/td)
rows = getNodeSet(node, ".//tr")
if(dropFirstRow)
rows = rows[-1]
els = lapply(rows, function(row) {
tmp = xpathSApply(row, "./th|./td", elFun)
if(trim)
trim(tmp)
else
tmp
})
# spans = getNodeSet(node, ".//td[@rowspan] | .//th[@rowspan]")
if(length(skip.rows)) {
infs = (skip.rows == Inf)
if(any(infs))
# want Inf - 2, Inf - 1, Inf, to indicate drop last 3, but that won't work
# take sequence of Inf to identify Inf - 2, Inf - 1, Inf
skip.rows[skip.rows == Inf] = length(els) - seq(0, length = sum(infs))
els = els[ - skip.rows ]
}
if(length(els) == 0)
return(NULL)
numEls = sapply(els, length)
# els[[1]] should be a scalar
if(is.logical(header) && !is.na(header) && header && any(nchar(els[[1]]) < 999)) {
header = els[[1]]
els = els[-1]
numEls = numEls[ - 1]
}
if(length(els) == 0)
return(NULL) #XXX we should have a header here so return a data frame with 0 rows.
ans = lapply(seq(length = max(numEls)),
function(col) {
sapply(els, `[`, col)
})
if(is.character(header) && length(header) == length(ans))
names(ans) = header
if(length(colClasses)) {
colClasses = rep(colClasses, length = length(ans))
n = sapply(colClasses, function(x) is.null(x) || x == "NULL")
if(any(n)) {
ans = ans[ ! n ]
colClasses = colClasses[ ! n ]
}
ans = lapply(seq(along = ans) ,
function(i)
if(is.function(colClasses[[i]]))
colClasses[[i]](ans[[i]])
else if(colClasses[[i]] == "factor")
factor(ans[[i]])
else if(colClasses[[i]] == "ordered")
ordered(ans[[i]])
else
as(ans[[i]], colClasses[[i]])
)
}
if(as.data.frame) {
ans = as.data.frame(ans, ...)
if(is.character(header) && length(header) == length(ans))
names(ans) = header
else if(nrow(ans) > 0)
names(ans) = paste("V", seq(along = ans), sep = "")
}
ans
})
getTableWithRowSpan =
function(node, r = xmlSize(node),
c = max(xmlSApply(node, function(x) length(getNodeSet(x, "./td | ./th")))),
encoding = 0L)
{
ans = matrix(NA_character_, r, c)
for(i in seq(length = r)) {
col = 1
kids = getNodeSet(node[[i]], "./th | ./td")
for(k in seq(along = kids)) {
sp = xmlGetAttr(k, "rowspan", 1)
ans[seq(i, length = sp)] = xmlValue(k, encoding = encoding)
}
}
}
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