通过多个分隔符拆分列，保留分隔符

Question

如何使用 %、- 和 + 作为可能的分隔符将字符列拆分为 3 列，并将分隔符保留在新列中？

示例数据：

data <- data.table(x=c("92.1%+100-200","90.4%-1000+200", "92.8%-200+100", "99.2%-500-200","90.1%+500-200"))

所需数据示例：

data.desired <- data.table(x1=c("92.1%", "90.4%", "92.8%","99.2%","90.1%")
                           , x2=c("+100","-1000","-200","-500","+500")
                           , x3=c("-200","+200","+100","-200","-200"))

很高兴为一个好的答案和对这个问题的一些帮助奖励积分！

Answer 1

我们可以使用separatefromtidyr进行分割，并使用正向前瞻来保留分隔符：

data %>% separate(x, c("x1", "x2", "x3"), sep = "(?=\\+|-)")
#       x1    x2   x3
# 1: 92.1%  +100 -200
# 2: 90.4% -1000 +200
# 3: 92.8%  -200 +100
# 4: 99.2%  -500 -200
# 5: 90.1%  +500 -200

也就是说，请注意，简单地拆分\\+|-我们会得到

data %>% separate(x, c("x1", "x2", "x3"), sep = "\\+|-")
#       x1   x2  x3
# 1: 92.1%  100 200
# 2: 90.4% 1000 200
# 3: 92.8%  200 100
# 4: 99.2%  500 200
# 5: 90.1%  500 200

在“无”处使用(?=\\+|-)split 以防紧接着我们有+or -（不匹配）。

Answer 2

data.table等价的是tstrsplit：

data[, c("x1","x2","x3") := tstrsplit(x, "(?<=.)(?=[+-])", perl=TRUE) ]
data
#                x    x1    x2   x3
#1:  92.1%+100-200 92.1%  +100 -200
#2: 90.4%-1000+200 90.4% -1000 +200
#3:  92.8%-200+100 92.8%  -200 +100
#4:  99.2%-500-200 99.2%  -500 -200
#5:  90.1%+500-200 90.1%  +500 -200