在 dplyr 中使用 case_when 改变新列时出现问题

Question

我想使用 this 数据帧上 Código 列的不同长度值来改变新列。

ods <- readODS::read_ods('http://www.arcotel.gob.ec/wp-content/uploads/2016/09/proyeccion_cantonal_total_2010-2020_seg%C3%BAn_INEC1.ods', skip = 2)

我试过在像这样的 mutate 中使用 case_when：

mutate(ods, Provincia = case_when(
        length(ods$Código) == 3 ~ str_extract(ods$Código, '[[:digit:]]{1}'),
        length(ods$Código) == 4 ~ str_extract(ods$Código, '[[:digit:]]{2}')
))

当其值的长度为 3 时，它应该用 Código 的第一个数字创建一个新的 Provincia 列，否则应该提取两个数字。当运行上面的代码我只得到NA的

Answer 1

使用nchar，这将计算每次观察中的字符数：

ods <- mutate(ods, Provincia = case_when(
         nchar(ods$Código) == 3 ~ str_extract(ods$Código, '[[:digit:]]{1}'),
         nchar(ods$Código) == 4 ~ str_extract(ods$Código, '[[:digit:]]{2}')
 ))

结果：

    > ods %>% pull(Provincia)
  [1] "1"  "1"  "1"  "1"  "1"  "1"  "1"  "1"  "1"  "1"  "1"  "1"  "1"  "1"  "1"  "2"  "2"  "2"  "2"  "2"  "2" 
 [22] "2"  "3"  "3"  "3"  "3"  "3"  "3"  "3"  "4"  "4"  "4"  "4"  "4"  "4"  "5"  "5"  "5"  "5"  "5"  "5"  "5" 
 [43] "6"  "6"  "6"  "6"  "6"  "6"  "6"  "6"  "6"  "6"  "7"  "7"  "7"  "7"  "7"  "7"  "7"  "7"  "7"  "7"  "7" 
 [64] "7"  "7"  "7"  "8"  "8"  "8"  "8"  "8"  "8"  "8"  "8"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9" 
 [85] "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "9"  "10" "10" "10" "10" "10" "10"
[106] "11" "11" "11" "11" "11" "11" "11" "11" "11" "11" "11" "11" "11" "11" "11" "11" "12" "12" "12" "12" "12"
[127] "12" "12" "12" "12" "12" "12" "12" "12" "13" "13" "13" "13" "13" "13" "13" "13" "13" "13" "13" "13" "13"
[148] "13" "13" "13" "13" "13" "13" "13" "13" "13" "14" "14" "14" "14" "14" "14" "14" "14" "14" "14" "14" "14"
[169] "15" "15" "15" "15" "15" "16" "16" "16" "16" "17" "17" "17" "17" "17" "17" "17" "17" "18" "18" "18" "18"
[190] "18" "18" "18" "18" "18" "19" "19" "19" "19" "19" "19" "19" "19" "19" "20" "20" "20" "21" "21" "21" "21"
[211] "21" "21" "21" "22" "22" "22" "22" "23" "24" "24" "24" "90" "90" "90"

在 dplyr 中使用 case_when 改变新列时出现问题

Trouble mutating new column using case_when in dplyr

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case-when

dplyr