R/cssExtract.R
In cuche27/CSS: Extract information from an html document with CSS selectors
Defines functions
cssLink
cssClass
cssId
cssSrc
cssValue
cssName
cssNumeric
cssCharacter
Documented in
cssCharacter
cssClass
cssId
cssLink
cssName
cssNumeric
cssSrc
cssValue
#' Extract value from an html element
#'
#' These functions have to be used in \code{\link{cssApply}} and
#' \code{\link{html2df}}. They aim to facilitate extraction of
#' different kind of value.
#'
#' \code{cssNumeric} extracts the numeric value of an element,
#' \code{cssCharacter} extracts text. \code{cssLink} extracts the url of a link.
#' \code{cssSrc}, \code{cssId}, \code{cssClass}, \code{cssName} and
#' \code{cssValue} are less usefull and extract respectively the source of an
#' element, its id, its css class, its name and its value (may be usefull for
#' input elements).
#'
#' @name cssExtract
#' @rdname cssExtract
#' @aliases cssLink
#'
#' @param node
#' An xml node
#' @param ...
#' Parameters passed to \code{\link{xmlValue}}
#'
#' @return All these function return a chracter string except \code{cssNumeric}
#' which returns a Numeric value
#'
#' @examples
#' doc <- "<html>
#' <head></head>
#' <body>
#' <div id='character1' class='character'>
#' <span class='name'>Mike</span>
#' <span class='level digit'>10</span>
#' <a href='http://someurl.com'>Complete profile</a>
#' </div>
#' <div id='character2' class='character'>
#' <span class='name'>Stan</span>
#' <a href='http://someurl2.com'>Complete profile</a>
#' </div>
#' </body>
#' </html>"
#'
#' doc <- htmlParse(doc)
#'
#' # Names of the characters
#' cssApply(doc, ".character>.name", cssCharacter)
#'
#' # Name of character1
#' cssApply(doc, "#character1>.name", cssCharacter)
#'
#' # Urls of the profiles
#' cssApply(doc, ".character>a", cssLink)
#'
#' # Level of characters
#' cssApply(doc, ".character>.level", cssNumeric)
#'
#' # character 2 does not have level, we would want to have a NA value instead of nothing
#' cssApplyInNodeSet(doc, ".character", ".level", cssNumeric)
#'
#' @export
cssLink <- function(node) {
# Pour extraire des liens
xmlGetAttr(node, name="href")
}
#' @rdname cssExtract
#' @export
cssClass <- function(node) {
xmlGetAttr(node, name="class")
}
#' @rdname cssExtract
#' @export
cssId <- function(node) {
xmlGetAttr(node, name="id")
}
#' @rdname cssExtract
#' @export
cssSrc <- function(node) {
xmlGetAttr(node, name="src")
}
#' @rdname cssExtract
#' @export
cssValue <- function(node) {
xmlGetAttr(node, name="value")
}
#' @rdname cssExtract
#' @export
cssName <- function(node) {
xmlGetAttr(node, name="name")
}
#' @rdname cssExtract
#' @export
cssNumeric <- function(node, ...) {
x <- xmlValue(node, ...)
x <- gsub("[^\\d\\.]", "", x, perl=TRUE)
x <- gsub("(^\\.+)|(\\.+$)", "", x)
x <- as.numeric(x)
}
#' @rdname cssExtract
#' @export
cssCharacter <- function(node, ...) {
xmlValue(node, ...)
}
cuche27/CSS documentation built on Oct. 20, 2019, 1:09 a.m.
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Defines functions cssLink cssClass cssId cssSrc cssValue cssName cssNumeric cssCharacter
Documented in cssCharacter cssClass cssId cssLink cssName cssNumeric cssSrc cssValue
#' Extract value from an html element
#'
#' These functions have to be used in \code{\link{cssApply}} and
#' \code{\link{html2df}}. They aim to facilitate extraction of
#' different kind of value.
#'
#' \code{cssNumeric} extracts the numeric value of an element,
#' \code{cssCharacter} extracts text. \code{cssLink} extracts the url of a link.
#' \code{cssSrc}, \code{cssId}, \code{cssClass}, \code{cssName} and
#' \code{cssValue} are less usefull and extract respectively the source of an
#' element, its id, its css class, its name and its value (may be usefull for
#' input elements).
#'
#' @name cssExtract
#' @rdname cssExtract
#' @aliases cssLink
#'
#' @param node
#' An xml node
#' @param ...
#' Parameters passed to \code{\link{xmlValue}}
#'
#' @return All these function return a chracter string except \code{cssNumeric}
#' which returns a Numeric value
#'
#' @examples
#' doc <- "<html>
#' <head></head>
#' <body>
#' <div id='character1' class='character'>
#' <span class='name'>Mike</span>
#' <span class='level digit'>10</span>
#' <a href='http://someurl.com'>Complete profile</a>
#' </div>
#' <div id='character2' class='character'>
#' <span class='name'>Stan</span>
#' <a href='http://someurl2.com'>Complete profile</a>
#' </div>
#' </body>
#' </html>"
#'
#' doc <- htmlParse(doc)
#'
#' # Names of the characters
#' cssApply(doc, ".character>.name", cssCharacter)
#'
#' # Name of character1
#' cssApply(doc, "#character1>.name", cssCharacter)
#'
#' # Urls of the profiles
#' cssApply(doc, ".character>a", cssLink)
#'
#' # Level of characters
#' cssApply(doc, ".character>.level", cssNumeric)
#'
#' # character 2 does not have level, we would want to have a NA value instead of nothing
#' cssApplyInNodeSet(doc, ".character", ".level", cssNumeric)
#'
#' @export
cssLink <- function(node) {
# Pour extraire des liens
xmlGetAttr(node, name="href")
}
#' @rdname cssExtract
#' @export
cssClass <- function(node) {
xmlGetAttr(node, name="class")
}
#' @rdname cssExtract
#' @export
cssId <- function(node) {
xmlGetAttr(node, name="id")
}
#' @rdname cssExtract
#' @export
cssSrc <- function(node) {
xmlGetAttr(node, name="src")
}
#' @rdname cssExtract
#' @export
cssValue <- function(node) {
xmlGetAttr(node, name="value")
}
#' @rdname cssExtract
#' @export
cssName <- function(node) {
xmlGetAttr(node, name="name")
}
#' @rdname cssExtract
#' @export
cssNumeric <- function(node, ...) {
x <- xmlValue(node, ...)
x <- gsub("[^\\d\\.]", "", x, perl=TRUE)
x <- gsub("(^\\.+)|(\\.+$)", "", x)
x <- as.numeric(x)
}
#' @rdname cssExtract
#' @export
cssCharacter <- function(node, ...) {
xmlValue(node, ...)
}
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