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我坚持将字符串转换为时间。我知道 Stack 上有很多关于将字符串转换为时间的主题，但是我无法用解决方案解决这个问题。

情况 我有一个这样的文件：

> dput(df$Time[1:50])
c("1744.3", "2327.54", "1718.51", "2312.3200000000002", "1414.16", 
"2046.15", "1442.5", "1912.22", "2303.2199999999998", "2146.3200000000002", 
"1459.02", "1930.15", "1856.23", "2319.15", "1451.05", "25.460000000000036", 
"1453.25", "2309.02", "2342.48", "2322.5300000000002", "2101.5", 
"2026.07", "1245.04", "1945.15", "5.4099999999998545", "1039.5", 
"1731.37", "2058.41", "2030.36", "1814.31", "1338.18", "1858.33", 
"1731.36", "2343.38", "1733.27", "2304.59", "1309.47", "1916.11", 
"1958.3", "1929.54", "1756.4", "1744.23", "1731.26", "1844.47", 
"1353.25", "1958.3", "1746.44", "1857.53", "2047.15", "2327.2199999999998", "1915"
)

在这个例子中，时间应该是这样的：

"1744.3"   = 17:44:30
"2327.54"  = 23:27:54
"1718.51"  = 17:18:51
"2312.3200000000002" = 23:12:32
...
"25.460000000000036" = 00:25:46 # as you can see, the first two 00 are missing.

“1915” = 19:15:00

但是，我尝试了多种方法（现在我什至被 str_replace() 困住了）。希望有人知道我可以如何改变这一点。

我尝试了什么？

format(df$Time, "%H%M.%S") # Yes I know... 

# So therefore I thought, lets replace the strings to get them in a proper format
# like HH:MM:SS. First step was to replace the "." for a ":" 

str_replace("." , ":", df$Time) # this was leading to "." (don't know why)

这就是我非常沮丧的一点，我把它贴在了 Stack 上。希望你们能帮助我。

提前谢谢了！

4

4 回答 4

2

这是一种方法，将输出存储在dputin 中x。

library(magrittr)

#Remove all the dots
gsub('\\.', '', x) %>%
  #Select only first 6 characters
  substr(1, 6) %>%
  #Pad 0's at the end
  stringr::str_pad(6,pad = '0', side = 'right') %>%
  #Add colon (:) separator
  sub('(.{2})(.{2})', '\\1:\\2:', .)

# [1] "17:44:30" "23:27:54" "17:18:51" "23:12:32" "14:14:16" "20:46:15"
# [7] "14:42:50" "19:12:22" "23:03:21" "21:46:32" "14:59:02" "19:30:15"
#[13] "18:56:23" "23:19:15" "14:51:05" "25:46:00" "14:53:25" "23:09:02"
#...

请注意，这也可以在没有管道的情况下完成，但为了清楚起见使用它。如果需要，您可以从这里将时间转换为POSIXct格式。

于 2020-02-19T10:04:58.510 回答
1

一种迂回的方式

tmp=as.numeric(lapply(strsplit(as.character(df$Time),"\\."),function(x){nchar(x[1])}))
ifelse(tmp>2,
       substr(as.POSIXct(df$Time,format="%H%M.%S"),12,19),
       substr(as.POSIXct(df$Time,format="%M.%S"),12,19))
于 2020-02-19T10:07:01.783 回答
1

主要问题是时间"25.460000000000036"。但我想我找到了一个清晰但有点冗长的解决方案：

library(tidyverse)

df %>% 
  mutate(hours = formatC(as.numeric(Time), width = 4, format = "d", flag = "0"),
         seconds = as.numeric(str_extract(Time, "[.].+")) * 100) %>% 
  mutate(Time_new = stringi::stri_datetime_parse(paste0(hours, seconds), format = "HHmm.ss"))
#> # A tibble: 51 x 4
#>    Time               hours seconds Time_new           
#>    <chr>              <chr>   <dbl> <dttm>             
#>  1 25.460000000000036 0025     46.  2020-02-19 00:25:46  # I changed the order of the times so the weird format is on top
#>  2 1744.3             1744     30   2020-02-19 17:44:30
#>  3 2327.54            2327     54   2020-02-19 23:27:54
#>  4 1718.51            1718     51   2020-02-19 17:18:51
#>  5 2312.3200000000002 2312     32.  2020-02-19 23:12:32
#>  6 1414.16            1414     16   2020-02-19 14:14:16
#>  7 2046.15            2046     15   2020-02-19 20:46:15
#>  8 1442.5             1442     50   2020-02-19 14:42:50
#>  9 1912.22            1912     22   2020-02-19 19:12:22
#> 10 2303.2199999999998 2303     22.0 2020-02-19 23:03:21
#> # ... with 41 more rows

如果您也有没有分数的时间（即没有点），您可以使用这种方法：

normalize_time <- function(t) {
  formatC(as.numeric(t) * 100, width = 6, format = "d", flag = "0")
}

df %>% 
  mutate(Time_new = as.POSIXct(normalize_time(Time), format = "%H%M%S"))
于 2020-02-19T10:10:52.263 回答
1

一种数据表方式

首先，将向量中的字符串转换为数字，乘以 100（以在小数分隔符之前获取 HMS 的相关部分）并设置为整数。然后使用sprintf()添加前导零以获得 6 位字符串。最后，换算成时间。

data.table::as.ITime( sprintf( "%06d", 
                               as.integer( as.numeric(time) * 100 ) ), 
                      format = "%H%M%S" )


# [1] "17:44:30" "23:27:54" "17:18:51" "23:12:32" "14:14:16" "20:46:15" "14:42:50" "19:12:22" "23:03:21" "21:46:32" "14:59:02" "19:30:15"
# [13] "18:56:23" "23:19:15" "14:51:05" "00:25:46" "14:53:25" "23:09:02" "23:42:48" "23:22:53" "21:01:50" "20:26:07" "12:45:04" "19:45:15"
# [25] "00:05:40" "10:39:50" "17:31:37" "20:58:41" "20:30:36" "18:14:31" "13:38:18" "18:58:33" "17:31:36" "23:43:38" "17:33:27" "23:04:59"
# [37] "13:09:47" "19:16:11" "19:58:30" "19:29:54" "17:56:40" "17:44:23" "17:31:26" "18:44:47" "13:53:25" "19:58:30" "17:46:44" "18:57:53"
# [49] "20:47:15" "23:27:21"
于 2020-02-19T10:27:50.183 回答