R 合并：‘；不适用‘；NA’；在结果中是重复的

我正在查看此链接中的示例代码

看起来数据集的位置发生了变化，所以我稍微修改了代码以适应这些变化

airports <- read.delim("https://raw.githubusercontent.com/jpatokal/openflights/master/data/airports.dat", sep=",")
colnames(airports) <- c("ID", "name", "city", "country", "IATA_FAA", "ICAO", "lat", "lon", "altitude", "timezone", "DST")
head(airports)

library(rworldmap)
newmap <- getMap(resolution = "low")
plot(newmap, xlim = c(-20, 59), ylim = c(35, 71), asp = 1)
points(airports$lon, airports$lat, col = "red", cex = .6)



routes <- read.csv("https://raw.githubusercontent.com/jpatokal/openflights/master/data/routes.dat", header=F)
colnames(routes) <- c("airline", "airlineID", "sourceAirport", "sourceAirportID", "destinationAirport", "destinationAirportID", "codeshare", "stops", "equipment")
head(routes)

library(plyr)
departures <- ddply(routes, .(sourceAirportID), "nrow")
names(departures)[2] <- "flights"
arrivals <- ddply(routes, .(destinationAirportID), "nrow")
names(arrivals)[2] <- "flights"

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机场首先，这些只是警告，不是错误。也就是说，一切仍然有效，但可能并非如预期的那样。问题源于

colnames(airports) <- c("ID", "name", "city", "country", "IATA_FAA", "ICAO", "lat", "lon", "altitude", "timezone", "DST")

colnames（机场）啊，是的！！这是有道理的。我做了你推荐的改变，现在一切都很好。像往常一样，我试图自己解决这个问题，这样我就不必问一个愚蠢的问题，但这个问题让我逃避了。再次感谢！！
colnames(airports) <- c("ID", "name", "city", "country", "IATA_FAA", "ICAO", "lat", "lon", "altitude", "timezone", "DST")