根据另一个数据帧中的行索引将 POSIXt 日期拉入另一个数据帧作为新列 - 可重现

发布于 2025-01-17 14:20:24 字数 978 浏览 5 评论 0原文

我在下面有数据框“ DF1”，其中包含与数据框架“ DF”行相关的行索引。

我想使用DF1中的行索引在DataFrame DF中引入相应的行。即，第一行DF1是4和6，我想在DF1中创建两个新列，它们是开始时间（DF第4行）和结束时间（DF第6行的时间戳）。

实际的数据范围要长得多，因此一般代码可以有所帮助

df1 <- structure(list(co2_start = c(4, 6, 9, 12), co2_end = c(6, 9, 
12, 15)), class = "data.frame", row.names = c(NA, -4L))
    
df <- structure(list(date = structure(c(1623481200, 1623481500, 1623481800, 
    1623482100, 1623482400, 1623482700, 1623483000, 1623483300, 1623483600, 
    1623483900, 1623484200, 1623484500, 1623484800, 1623485100, 1623485400
    ), class = c("POSIXct", "POSIXt"), tzone = "")), row.names = c(NA, 
    -15L), class = "data.frame")

，因此我希望DF1看起来像下面

4     6     2021-06-12 00:15:00     2021-06-12 00:25:00
6     9     2021-06-12 00:25:00     2021-06-12 00:40:00
9     12    2021-06-12 00:40:00     2021-06-12 00:55:00
12    15    2021-06-12 00:55:00     2021-06-12 01:10:00

原文

I have the dataframe "df1" below which contains row indices that relate to the rows of data frame "df".

I want to use the row indices in df1 to bring in the corresponding row in the dataframe df. i.e., the first row df1 is 4 and 6 and I want to create two new columns in df1 that are start time (timestamp on row 4 of df) and end time (timestamp on row 6 of df).

Actual dataframes are much longer so general code to do this would help

df1 <- structure(list(co2_start = c(4, 6, 9, 12), co2_end = c(6, 9, 
12, 15)), class = "data.frame", row.names = c(NA, -4L))
    
df <- structure(list(date = structure(c(1623481200, 1623481500, 1623481800, 
    1623482100, 1623482400, 1623482700, 1623483000, 1623483300, 1623483600, 
    1623483900, 1623484200, 1623484500, 1623484800, 1623485100, 1623485400
    ), class = c("POSIXct", "POSIXt"), tzone = "")), row.names = c(NA, 
    -15L), class = "data.frame")

So I would like df1 to look like below

4     6     2021-06-12 00:15:00     2021-06-12 00:25:00
6     9     2021-06-12 00:25:00     2021-06-12 00:40:00
9     12    2021-06-12 00:40:00     2021-06-12 00:55:00
12    15    2021-06-12 00:55:00     2021-06-12 01:10:00

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紅太極 2025-01-24 14:20:24

由于您的df1已经是行索引，因此您只需使用dplyr :: mutate（）创建列并在开始/结束列中的值子集。

library(tidyverse)

df1 <- structure(list(co2_start = c(4, 6, 9, 12), co2_end = c(6, 9, 12, 15)), class = "data.frame", row.names = c(NA, -4L))
df <- structure(list(date = structure(c(1623481200, 1623481500, 1623481800, 1623482100, 1623482400, 1623482700, 1623483000, 1623483300, 1623483600, 1623483900, 1623484200, 1623484500, 1623484800, 1623485100, 1623485400), class = c("POSIXct", "POSIXt"), tzone = "")), row.names = c(NA, -15L), class = "data.frame")

df1 %>% 
  mutate(start = df$date[co2_start],
         end = df$date[co2_end])
#>   co2_start co2_end               start                 end
#> 1         4       6 2021-06-12 07:15:00 2021-06-12 07:25:00
#> 2         6       9 2021-06-12 07:25:00 2021-06-12 07:40:00
#> 3         9      12 2021-06-12 07:40:00 2021-06-12 07:55:00
#> 4        12      15 2021-06-12 07:55:00 2021-06-12 08:10:00

^由

Since your df1 are already row indices, you can just use dplyr::mutate() to create your columns and subset with the values in start/end columns.

library(tidyverse)

df1 <- structure(list(co2_start = c(4, 6, 9, 12), co2_end = c(6, 9, 12, 15)), class = "data.frame", row.names = c(NA, -4L))
df <- structure(list(date = structure(c(1623481200, 1623481500, 1623481800, 1623482100, 1623482400, 1623482700, 1623483000, 1623483300, 1623483600, 1623483900, 1623484200, 1623484500, 1623484800, 1623485100, 1623485400), class = c("POSIXct", "POSIXt"), tzone = "")), row.names = c(NA, -15L), class = "data.frame")

df1 %>% 
  mutate(start = df$date[co2_start],
         end = df$date[co2_end])
#>   co2_start co2_end               start                 end
#> 1         4       6 2021-06-12 07:15:00 2021-06-12 07:25:00
#> 2         6       9 2021-06-12 07:25:00 2021-06-12 07:40:00
#> 3         9      12 2021-06-12 07:40:00 2021-06-12 07:55:00
#> 4        12      15 2021-06-12 07:55:00 2021-06-12 08:10:00

^{Created on 2022-03-29 by the reprex package (v2.0.1)}

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