將列字符串轉換為r數據框中的數字

Question

我有一個數據框，其中包含一列字符串，如下所示：

    mydata <- c("-1.356670,35.355030",
            "-1.356670,35.355030", 
            "-1.356620,35.355890", 
            "-1.356930,35.358660", 
            "-1.357000,35.359060"
    )

    df <- data.frame(mydata)

我想將它轉換為包含兩列“ long和lat ，每個都是數字類型的數據lapply 。這樣做的最佳方法是什么？我嘗試過使用lapply ，但似乎無法使其工作。

Answer 1

使用基數R，您可以：

df$Long <- as.numeric(sapply(strsplit(as.character(df$mydata), ","), function(x) x[1]))
df$Lat <- as.numeric(sapply(strsplit(as.character(df$mydata), ","), function(x) x[2]))

               mydata     Long      Lat
1 -1.356670,35.355030 -1.35667 35.35503
2 -1.356670,35.355030 -1.35667 35.35503
3 -1.356620,35.355890 -1.35662 35.35589
4 -1.356930,35.358660 -1.35693 35.35866
5 -1.357000,35.359060 -1.35700 35.35906

或與tstrsplit()從data.table ：

df$Long <- as.numeric(tstrsplit(df$mydata, ",")[[1]])
df$Lat <- as.numeric(tstrsplit(df$mydata, ",")[[2]])

另外隨着tstrsplit()從data.table提議@clmarquart：

setDT(df)[, c("lat", "long") := tstrsplit(mydata, ",", fixed = TRUE)]

Answer 2

這可以在基數R中的一行中完成：

read.table(text = as.character(df$mydata), sep = ",", col.names = c("long", "lat"))

贈送：

     long      lat
1 -1.35667 35.35503
2 -1.35667 35.35503
3 -1.35662 35.35589
4 -1.35693 35.35866
5 -1.35700 35.35906

Answer 3

一個tidyverse解決方案。

library(tidyverse)

dat <- df %>%
  separate(mydata, into = c("Long", "Lat"), sep = ",", convert = TRUE)

# Print the data
dat
#       Long      Lat
# 1 -1.35667 35.35503
# 2 -1.35667 35.35503
# 3 -1.35662 35.35589
# 4 -1.35693 35.35866
# 5 -1.35700 35.35906

Answer 4

使用strsplit和do.call ，我們只需要分配列名

newdf=do.call(rbind.data.frame, strsplit(mydata,','))
names(newdf)=c('long','lat')
newdf
       long       lat
1 -1.356670 35.355030
2 -1.356670 35.355030
3 -1.356620 35.355890
4 -1.356930 35.358660
5 -1.357000 35.359060