r - 按 `-` 拆分 r 中的月/年字符串

Question

我有一列如下;

   fiscal_year_end
1             1231
2             1231
3             1231
4             1231
5              202
6             1231
7             1231
8              202
9             1231
10             927

它们对应于月份，即 12-31 , 9-27和 20-2 .

我正在尝试将它们放入那种格式，但似乎无法正确处理。

我试过了str_replace_all(df$fiscal_year_end, "(?<=^\\d{2}|^\\d{4})", "-")使用 stringr包，但它没有像我预期的那样出来。

我哪里出错了？

数据:

structure(list(fiscal_year_end = c(1231L, 1231L, 1231L, 1231L, 
202L, 1231L, 1231L, 202L, 1231L, 927L, 228L, 1231L, 1231L, 1231L, 
1231L, 928L, 1231L, 1231L, 930L, 1231L, 1231L, 628L, 1231L, 1231L, 
1228L, 930L, 1231L, 1231L, 1231L, 1231L, 927L, 630L, 1231L, 202L, 
1231L, 1231L, 1231L, 1231L, 927L, 930L, 1231L, 1231L, 1231L, 
1231L, 228L, 928L, 1231L, 1231L, 1231L, 1231L, 1231L, 1231L, 
1231L, 1231L, 1231L, 1231L, 1228L, 1231L, 1231L, 1231L, 1231L, 
131L, 1231L, 1231L, 1231L, 1231L, 1231L, 1231L, 930L, 1231L, 
1231L, 1231L, 1231L, 1231L, 1231L, 1231L, 831L, 1231L, 102L, 
1231L, 1231L, 1231L, 1130L, 1231L, 1228L, 1231L, 1231L, 1231L, 
1231L, 1231L, 1231L, 1231L, 1231L, 1231L, 930L, 1031L, 1231L, 
1231L, 1231L, 1231L, 1231L, 1231L, 203L, 1231L, 1231L, 1231L, 
1231L, 1231L, 1229L, 1231L, 1231L, 1231L, 426L, 1231L, 1231L, 
1231L, 1231L, 1231L, 1231L, 1231L, 1231L, 1231L, 202L, 1231L, 
1231L, 1231L, 1231L, 1231L, 1231L, 1229L, 1231L, 1231L, 630L, 
1231L, 1231L, 1209L, 1231L, 1231L, 1231L, 728L, 1231L, 1231L, 
1231L, 1231L, 1231L, 1231L, 630L, 1231L, 1231L, 1231L, 1231L, 
1231L, 1231L, 727L, 1231L, 201L, 1231L, 1231L, 1231L, 1231L, 
1231L, 630L, 1231L, 1231L, 1231L, 1130L, 1231L, 1231L, 1231L, 
1231L, 1231L, 1231L, 1231L, 930L, 930L, 1231L, 1231L, 331L, 1231L, 
1231L, 1231L, 1231L, 1231L, 1231L, 1231L, 1031L, 1229L, 1231L, 
1231L, 1231L, 201L, 1231L, 1231L, 1231L, 1231L, 1231L, 1231L, 
831L, 630L, 831L)), row.names = c(NA, -200L), .internal.selfref = <pointer: 0x0000000002511ef0>, class = "data.frame")

编辑:

     datadate fiscal_year_end
1  2012-08-31             831
2  2017-01-31             201
3  1999-12-31            1231
4  2009-02-28             228
5  2010-12-31            1231
6  2005-12-31            1231
7        <NA>             630
8  2010-09-30             928
9  2009-09-30             930
10 2018-01-31             201
11 2017-12-31            1231
12 2004-12-31            1231

Answer 1

格式化为4位后我们可以分离

library(dplyr)
library(tidyr)
df1 %>% 
  mutate(fiscal_year_end =  sprintf("%04d", fiscal_year_end)) %>% 
  separate(fiscal_year_end, c("month", "day"), sep= 2)

或者在separate中使用负索引

df1 %>% 
  separate(fiscal_year_end, c("month", "day"), sep= -2)

---

或者使用only base R，我们使用sub 创建一个定界符(仅使用单个捕获组)并将其转换为两个带有 read.csv

的列 data.frame

out <- read.csv(text = sub("(\\d{2})$", ",\\1", df1[[1]]), header = FALSE,
       col.names = c("month", "day"), stringsAsFactors = FALSE)

head(out, 5)
#  month day
#1    12  31
#2    12  31
#3    12  31
#4    12  31
#5     2   2