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[英]How to assign ID to multiple rows based on a value in 1 column in 1 row duplicating a value in a DIFFERENT column in a different row in R?
[英]R- How to move value in a specific column to a different row based on a value in a different column
假設我有以下數據框:
Seconds = c(0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3)
Markers= c("NA", "NA", "Start", "NA", "NA", "NA", "NA", "NA", "NA", "NA", "NA", "NA", "NA", "NA")
df = data.frame(Seconds, Markers)
我想將“標記”列中“開始”指示的值向下移動其列(或新列)0.5秒。 這可能是一個結果:
Seconds = c(0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3)
Markers2= c("NA", "NA", "NA", "NA", "NA", "NA", "NA", "Seconds", "NA", "NA", "NA", "NA", "NA", "NA")
df2 = data.frame(Seconds, Markers2)
或者,如果更容易實現,這將起作用:
Seconds = c(0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3)
Markers2= c("NA", "NA", "NA", "NA", "NA", "NA", "NA", "Seconds", "NA", "NA", "NA", "NA", "NA", "NA")
df3 = data.frame(Seconds, Markers, Markers2)
我想也許我可以做這樣的事情:
df$MarkerReal <- NA
df$MarkerReal [which(df$Markers == 'Start') + 5] <- 'Start'
這適用於本示例,但是我正在使用的實際數據對毫秒敏感,具有數千行的時間。 我不需要移動指定數量的行,而是將其基於該值,在此示例中,將其移動了半秒。
有任何想法嗎?
這是一個選項:
curr.pos <- which(df$Markers == "Start")[[1]] # taking first "Start" in case you have more than one
new.pos <- with(df, max(which(Seconds <= Seconds[[curr.pos]] + 0.5)))
df$Markers[c(curr.pos, new.pos)] <- c("NA", "Start")
產生:
Seconds Markers
1 0.0 NA
2 0.1 NA
3 0.2 NA
4 0.3 NA
5 0.4 NA
6 0.5 NA
7 0.6 NA
8 0.7 Start
9 0.8 NA
10 0.9 NA
11 1.0 NA
12 1.1 NA
13 1.2 NA
14 1.3 NA
當然,這假定您的DF按“ Seconds
列進行排序。
作為附帶說明,您應該考慮使用真實的NA(即NA_character_
),而不是具有“ NA”值的字符串。
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