r - 如何将货币和值(value)拆分到不同的列中

Question

我有一个包含股票数据的数据框:

stock,value
stock1,$30
stock2,£31
stock3,$50

如何溢出列值以获得两列货币和值(value)。输出示例:

stock,currency,value
stock1,$,30
stock2,£,31
stock3,$,50

Answer 1

尝试

library(data.table)#v1.9.5+
setDT(df1)[, c('currency', 'value') :=tstrsplit(value,
             '(?<=[^0-9])', perl=TRUE, type.convert=TRUE)]
df1
#    stock value currency
#1: stock1    30        $
#2: stock2    31        £
#3: stock3    50        $

或者

library(tidyr)
extract(df1, value, into=c('currency', 'value'), '([^0-9]+)(.*)')
#    stock currency value
#1 stock1        $    30
#2 stock2        £    31
#3 stock3        $    50

或者使用base R

cbind(df1[1],read.table(text=sub('(?<=[^0-9])', ' ', df1$value, 
                perl=TRUE), col.names=c('currency', 'value')))
#    stock currency value
#1 stock1        $    30
#2 stock2        £    31
#3 stock3        $    50

数据

df1 <- structure(list(stock = c("stock1", "stock2", "stock3"), 
value = c("$30", 
"£31", "$50")), .Names = c("stock", "value"), class = "data.frame", 
row.names = c(NA, -3L))