Question

我有两列，weight和area。我想按如下方式创建两列：

out1：如果weight＆gt; 12，顶部，否则下来。
out2：如果area＆gt; -0.5，插入值0.否则将area的绝对值四舍五入为0.5，映射为1。

期望的输出：

       weight   area    out1    out2
           12      3    down       0
           13   -0.4     top       0
           11    2.5    down       0
           17   -0.5     top       1
           16   -3.7     top       4
           14   -1.2     top       1
           11   -4.8    down       5

Answer 1

尝试

transform(df, out1=c('down', 'top')[(weight>12)+1L], 
                   out2= ifelse(area >-0.5, 0, abs(round2(area,0))))
#   weight area out1 out2
#1     12  3.0 down    0
#2     13 -0.4  top    0
#3     11  2.5 down    0
#4     17 -0.5  top    1
#5     16 -3.7  top    4
#6     14 -1.2  top    1
#7     11 -4.8 down    5

或者

library(data.table)
setDT(df)[, paste0('out',1:2) := list(c('down', 'top')[(weight>12)+1L],
               ifelse(area > -0.5, 0, abs(round2(area,0))))][]

其中round2是（摘自Round up from .5 in R）

  round2 = function(x, n) {
  posneg = sign(x)
  z = abs(x)*10^n
  z = z + 0.5
  z = trunc(z)
  z = z/10^n
  z*posneg
   }

Answer 2

以下是我使用data.table：

执行此操作的方法

require(data.table)
dt[, out1 := "down"][weight > 12, out1 := "top"]
dt[, out2 := floor(abs(area)+0.5)][area > -0.5, out2 := 0]
#    weight area out1 out2
# 1:     12  3.0 down    0
# 2:     13 -0.4  top    0
# 3:     11  2.5 down    0
# 4:     17 -0.5  top    1
# 5:     16 -3.7  top    4
# 6:     14 -1.2  top    1
# 7:     11 -4.8 down    5

Answer 3

df <- data.frame(weight= c(12, 13, 11, 17, 16, 14, 11),
                 area  = c(3, -0.4, 2.5, -0.5, -3.7, -1.2, -4.8))

df$out1 <- ifelse(df$weight > 12, "top", "down")
df$out2 <- ifelse(df$area > -0.5, 0, floor(0.5 + abs(df$area)))

df

#   weight area out1 out2
# 1     12  3.0 down    0
# 2     13 -0.4  top    0
# 3     11  2.5 down    0
# 4     17 -0.5  top    1
# 5     16 -3.7  top    4
# 6     14 -1.2  top    1
# 7     11 -4.8 down    5

r中的条件语句在两列中

3 个答案: