根据R中观察到的行，在前一行和后一行（日期）上添加值 [英] Add value on preceding and succeeding rows ( dates) based on observed row in R

问题描述

我有这个 df ，我想在其中添加一列，其中前一行和后一行的观察值填充为与观察值相同的值（现在为NA ）。
我玩了，但是没有成功。

i have this df where i want to add a column where observed values on immediately preceding and succeeding rows are filled with the same value as observed ( right now are as NA). I played around however no success.

这是我有的样本 df 和 dffilled 是我想要的。

Here is the sample df i have and dffilled is what i want to make it.

    dput(df)
structure(list(Date = structure(c(1L, 12L, 23L, 26L, 27L, 28L, 
29L, 30L, 31L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 13L, 
14L, 15L, 16L, 17L, 18L, 19L, 20L, 21L, 22L, 24L, 25L, 32L, 43L, 
54L, 55L, 56L, 57L, 58L, 59L, 60L, 33L, 34L, 35L, 36L, 37L, 38L, 
39L, 40L, 41L, 42L, 44L, 45L, 46L, 47L, 48L, 49L, 50L, 51L, 52L, 
53L), .Label = c("5/1/2012", "5/10/2012", "5/11/2012", "5/12/2012", 
"5/13/2012", "5/14/2012", "5/15/2012", "5/16/2012", "5/17/2012", 
"5/18/2012", "5/19/2012", "5/2/2012", "5/20/2012", "5/21/2012", 
"5/22/2012", "5/23/2012", "5/24/2012", "5/25/2012", "5/26/2012", 
"5/27/2012", "5/28/2012", "5/29/2012", "5/3/2012", "5/30/2012", 
"5/31/2012", "5/4/2012", "5/5/2012", "5/6/2012", "5/7/2012", 
"5/8/2012", "5/9/2012", "6/1/2012", "6/10/2012", "6/11/2012", 
"6/12/2012", "6/13/2012", "6/14/2012", "6/15/2012", "6/16/2012", 
"6/17/2012", "6/18/2012", "6/19/2012", "6/2/2012", "6/20/2012", 
"6/21/2012", "6/22/2012", "6/23/2012", "6/24/2012", "6/25/2012", 
"6/26/2012", "6/27/2012", "6/28/2012", "6/29/2012", "6/3/2012", 
"6/4/2012", "6/5/2012", "6/6/2012", "6/7/2012", "6/8/2012", "6/9/2012"
), class = "factor"), Obs = c(NA, NA, NA, NA, NA, NA, NA, NA, 
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 320L, NA, NA, 
NA, NA, NA, NA, NA, NA, 321L, 321L, 322L, NA, NA, NA, NA, NA, 
NA, NA, NA, NA, 323L, NA, NA, NA, NA, 324L, NA, NA, NA, NA, NA, 
NA, NA, NA, NA, NA, NA, 325L, NA)), .Names = c("Date", "Obs"), class = "data.frame", row.names = c(NA, 
-60L))

我希望最终数据框为 dffilled ，位于下面的紧接观察日期之前和之后将填充观察值。

I want the final data frame as dffilled below where immediate previous and immediate after observation dates will be filled with the observed value.

    dput(dffilled)
structure(list(Date = structure(c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 
8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 20L, 
21L, 22L, 23L, 34L, 36L, 37L, 38L, 39L, 40L, 41L, 42L, 24L, 25L, 
26L, 27L, 28L, 29L, 30L, 31L, 32L, 33L, 35L), .Label = c("5/10/2012", 
"5/11/2012", "5/12/2012", "5/13/2012", "5/14/2012", "5/15/2012", 
"5/16/2012", "5/17/2012", "5/18/2012", "5/19/2012", "5/20/2012", 
"5/21/2012", "5/22/2012", "5/23/2012", "5/24/2012", "5/25/2012", 
"5/26/2012", "5/27/2012", "5/28/2012", "5/29/2012", "5/30/2012", 
"5/31/2012", "6/1/2012", "6/10/2012", "6/11/2012", "6/12/2012", 
"6/13/2012", "6/14/2012", "6/15/2012", "6/16/2012", "6/17/2012", 
"6/18/2012", "6/19/2012", "6/2/2012", "6/20/2012", "6/3/2012", 
"6/4/2012", "6/5/2012", "6/6/2012", "6/7/2012", "6/8/2012", "6/9/2012"
), class = "factor"), Obs = c(NA, NA, NA, NA, NA, NA, NA, NA, 
NA, NA, NA, 320L, NA, NA, NA, NA, NA, NA, NA, NA, 321L, 321L, 
322L, NA, NA, NA, NA, NA, NA, NA, NA, NA, 323L, NA, NA, NA, NA, 
324L, NA, NA, NA, NA), Obs_filled = c(NA, NA, NA, NA, NA, NA, 
NA, NA, NA, NA, 320L, 320L, 320L, NA, NA, NA, NA, NA, NA, 321L, 
321L, 321L, 322L, 322L, NA, NA, NA, NA, NA, NA, NA, 323L, 323L, 
323L, NA, NA, 324L, 324L, 324L, NA, NA, NA)), .Names = c("Date", 
"Obs", "Obs_filled"), class = "data.frame", row.names = c(NA, 
-42L))

任何帮助将不胜感激。

推荐答案

一个想法是使用 dplyr 。我们创建两个新列， Obs1 ，这是 Obs 和的1个位置滞后Obs2 ，是 Obs 的1位领先者。然后，我们使用 coalesce 将三个列合并在一起。最后，我们删除不需要的列。

One idea is to use dplyr. We create two new columns, Obs1, which is a 1 position lag of Obs, and Obs2 which is a 1 position lead of Obs. We then use coalesce to "merge" the three Obs columns together. Finally we drop the unwanted columns.

library(dplyr)
df %>% 
 mutate(Obs1 = lag(Obs), Obs2 = lead(Obs), Obs = coalesce(Obs, Obs1, Obs2)) %>%
 select(-c(Obs1, Obs2))

#...
#18 5/18/2012  NA
#19 5/19/2012  NA
#20 5/20/2012 320
#21 5/21/2012 320
#22 5/22/2012 320
#23 5/23/2012  NA
#24 5/24/2012  NA
#25 5/25/2012  NA
#26 5/26/2012  NA
#27 5/27/2012  NA
#28 5/28/2012  NA
#29 5/29/2012 321
#30 5/30/2012 321
#31 5/31/2012 321
#32  6/1/2012 322
#33  6/2/2012 322
#34  6/3/2012  NA
#35  6/4/2012  NA
#...

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