列上的data.table子字符串

Question

鉴于此data.table

DT = data.table(item=c("item1 - description one", "item2 - description two", "item3 - description three"), sales=1:3)

DT
                        item sales
1:   item1 - description one     1
2:   item2 - description two     2
3: item3 - description three     3

如何轻松获得类似

的输出

      code sales
1:   item1     1
2:   item2     2
3:   item3     3

可能很容易，但提前谢谢。

Answer 1

你可以这样做：

DT[, item:=gsub(item, pattern=" - [a-zA-Z ]+", replacement="")]
setnames(DT, "item", "code")

#    code sales
#1: item1     1
#2: item2     2
#3: item3     3