Question

我有一个数据集，其中包含所有美国城市的纬度和经度。我想将纬度和经度分配给df。但是，有多个城市有不同的国家。如何将Lat和Lon分配到正确的城市和州？

Cities <- data.frame(City = c("Sunnyvale", "Sunnyvale","Sunnyvale","Sunnyvale"), 
       State = c("CA","MO", "NC", "TX"),
       Lat = c(37.36889,    37.05083,   35.73889,   32.79639 ),
       Lon = c(-122.03528,  -94.495,    -82.13611,  -96.56056))

df <- data.frame(City2 = c("Sunnyvale", "Sunnyvale"),
             State2 = c("CA", "NC"))

Answer 1

我们可以在“州”和“城市”列上使用join

library(data.table)
setDT(df)[Cities, c("Lat", "Lon") := .(Lat, Lon), on = .(City2 = City, State2 = State)]
df
#       City2 State2      Lat        Lon
#1: Sunnyvale     CA 37.36889 -122.03528
#2: Sunnyvale     NC 35.73889  -82.13611

Answer 2

使用left_join＆＃39; s > library(dplyr) > left_join(df, Cities, by = c("City2" = "City", "State2" = "State")) City2 State2 Lat Lon 1 Sunnyvale CA 37.36889 -122.03528 2 Sunnyvale NC 35.73889 -82.13611：

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R：使用两个常用值分配或合并

2 个答案: