R/merge.R

In geovec: Manipulation of geographic vector (points, lines, polygons) data

# Author: Robert J. Hijmans
# Date : November 2011
# Version 1.0
# Licence GPL v3


setMethod('merge', signature(x='Spatial', y='data.frame'), 
function(x, y, by=intersect(names(x), names(y)), by.x=by, by.y=by, all.x=TRUE, suffixes = c(".x",".y"), incomparables = NULL, ...) {
	if (!'data' %in% slotNames(x)) {
		stop('x has no data.frame')
	}
	d <- x@data
	d$donotusethisvariablename976 <- 1:nrow(d)
	
	y <- unique(y)
	i <- apply(y[, by.y, drop=FALSE], 1, paste) %in% apply(x@data[, by.x, drop=FALSE], 1, paste)
	y <- y[i, ,drop=FALSE]
	if (isTRUE(any(table(y[, by.y]) > 1))) {
		stop("'y' has multiple records for one or more 'by.y' key(s)")
	}
	
	if (!all.x) {
		y$donotusethisvariablename679 <- 1
	}
	
	d <- merge(d, y, by=by, by.x=by.x, by.y=by.y, suffixes=suffixes, incomparables=incomparables, all.x=TRUE, all.y=FALSE)
	d <- d[order(d$donotusethisvariablename976), ]
	d$donotusethisvariablename976 <- NULL
	rownames(d) <- row.names(x)
	x@data <- d

	if (! all.x ) {
		x <- x[!is.na(x@data$donotusethisvariablename679),  ,drop=FALSE] 
		x@data$donotusethisvariablename679 <- NULL
	}
	x
} 
)