如何强制阅读器考虑正确的十进制/分组标记？

Question

具有具有欧洲数字格式样式（1234.56-> 1.234,56）的csv文件，应使用readr函数或fread()处理。尽管read_csv2()应该专门为该任务而设计，但它基本上忽略了该规范。它只会猜测数字会自动格式化。如果前四个数字以上的数字仅出现在文件的末尾，即到达guess_max之后（默认为1000），则会出现问题。

我如何以编程方式强制执行正确的格式？

library(readr)

data <- data.frame(var1 = c("", 4, 5, "124.392,45"),
                   var2 = c(1, 2, "4.783.194,43", 7))
write_csv2(data, "data.csv")

read_csv2("data.csv", guess_max = 2, 
          locale = locale(decimal_mark = ",", grouping_mark = "."))
# # A tibble: 4 x 2
#   var1  var2
#   <dbl> <dbl>
# 1    NA     1
# 2     4     2
# 3     5    NA
# 4    NA     7

read_csv2("data.csv", guess_max = 3, 
          locale = locale(decimal_mark = ",", grouping_mark = "."))
# # A tibble: 4 x 2
#   var1  var2
#   <dbl> <dbl>
# 1    NA     1
# 2     4     2
# 3     5    4783194.
# 4    NA     7

read_delim("data.csv", delim = ";", guess_max = 3, 
          locale = locale(decimal_mark = ",", grouping_mark = "."))
# # A tibble: 4 x 2
#   var1  var2
#   <dbl> <dbl>
# 1    NA     1
# 2     4     2
# 3     5    4783194.
# 4    NA     7

Answer 1

预先设置col_types似乎有帮助。在这种情况下为数字。

result <- read_csv2("data.csv", 
          guess_max = 2,
          col_types = "nn",
          locale = locale(decimal_mark = ",", grouping_mark = "."))

result
# A tibble: 4 x 2
     var1     var2
    <dbl>    <dbl>
1     NA        1 
2      4        2 
3      5  4783194.
4 124392.       7