-1
我有一個數據幀(df
):其中包含條目的順序兩因素GROUP_BY然後添加行數R dplyr
a <- c("up","up","up","up","down","down","down","down")
b <- c("l","r","l","r","l","l","r","r")
df <- data.frame(a,b)
我想添加第三個柱(c
),通過a
列分組和b
,看起來是這樣的:
a b c
1 up l 1
2 up r 1
3 up l 2
4 up r 2
5 down l 1
6 down l 2
7 down r 1
8 down r 2
我曾嘗試使用dplyr解決方案都沒有奏效:
order <- df %>%
group_by(a) %>%
group_by(b) %>%
mutate(c = row_number()) # This counts the order based on `b`, ignoring `a`
order <- df %>%
group_by(a) %>%
group_by(b) %>%
mutate(c = seq_len(n())) # This counts the order based on `b`, ignoring `a`
我寧願如果可能的話用dplyr和管道保持,但其他建議,歡迎
group_by(a,b)而不是2個group_by語句有什麼問題? –
請注意,默認情況下'group_by'會覆蓋以前的組。要麼使用單個調用,要麼使用'add = TRUE'。 – Axeman