列組中最小的返回值

我有一組列，我需要一個新列min123，這些列的最小值爲123a_1到123a_5。列組中最小的返回值

dff <- structure(list(`MCI ID` = c("070405344", "230349820", "260386435","370390587", "380406805", "391169282", "440377986", "750391394","890373764", "910367024"), 
         `123a_1` = structure(c(16672, 16372,16730, 16688, 16700, 16783, 16709, 17033, 16786, 16675), class = "Date"), 
         `123a_2` = structure(c(17029, 16422, 17088, 17036, 17057,17140, 17072, 17043, 17141, 17038), class = "Date"), 
         `123a_3` = structure(c(NA_real_,NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_,NA_real_, NA_real_, NA_real_), class = "Date"), 
         `123a_4` = structure(c(NA_real_,NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_,NA_real_, NA_real_, NA_real_), class = "Date"), 
         `123a_5` = structure(c(NA_real_,NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_,NA_real_, NA_real_, NA_real_), class = "Date")), 
     .Names = c("MCI ID","123a_1", "123a_2", "123a_3", "123a_4", "123a_5"), row.names = c(NA,10L), class = "data.frame")

來源

2017-02-06 Jeremy R. Johnson

library(dplyr)  
dff %>% 
    mutate(min123 = pmin(`123a_1`, `123a_2`, `123a_3`, `123a_4`, `123a_5`, na.rm = T))

來源

2017-02-06 14:57:25 GGamba

也非常完美，第二個到，有沒有辦法回到旁邊的最小值？ –

這就是功能pmin是：

> str(dff) 
'data.frame': 10 obs. of 6 variables: 
$ MCI ID: chr "070405344" "230349820" "260386435" "370390587" ... 
$ 123a_1: Date, format: "2015-08-25" "2014-10-29" "2015-10-22" ... 
$ 123a_2: Date, format: "2016-08-16" "2014-12-18" "2016-10-14" ... 
$ 123a_3: Date, format: NA NA NA ... 
$ 123a_4: Date, format: NA NA NA ... 
$ 123a_5: Date, format: NA NA NA ... 
> dff$groupmin <- pmin(dff[[2]],dff[[3]],dff[[4]], dff[[5]], dff[[6]], na.rm=TRUE) 
> head(dff) 
    MCI ID  123a_1  123a_2 123a_3 123a_4 123a_5 groupmin 
1 070405344 2015-08-25 2016-08-16 <NA> <NA> <NA> 2015-08-25 
2 230349820 2014-10-29 2014-12-18 <NA> <NA> <NA> 2014-10-29 
3 260386435 2015-10-22 2016-10-14 <NA> <NA> <NA> 2015-10-22 
4 370390587 2015-09-10 2016-08-23 <NA> <NA> <NA> 2015-09-10 
5 380406805 2015-09-22 2016-09-13 <NA> <NA> <NA> 2015-09-22 
6 391169282 2015-12-14 2016-12-05 <NA> <NA> <NA> 2015-12-14

來源

2017-02-06 15:18:52 Bernhard

這與'dplyr'解決方案完全相同 – Sotos

@Sotos對於一個正在爲這樣一個簡單問題而苦苦掙扎的人，我給出了一個簡單的答案。通過使用非標準庫和通過管道的非標準語法引入的額外複雜性似乎不利於證明另一個答案。這並不重要，因爲Jaap目前有最好的答案：標準R和簡潔！（有我的upvote） – Bernhard

好的。如果你認爲它有價值，那麼通過一切手段。 – Sotos

使用do.call和pmin一個基礎R方法：

dff$min123 <- do.call(pmin, c(dff[-1], na.rm = TRUE))

類似appraoch在dplyr：

library(dplyr)  
dff %>% 
    mutate(min123 = do.call(pmin, c(select(., -1), na.rm = TRUE)))

或者data.table：

library(data.table) 
setDT(dff)[, min123 := do.call(pmin, c(.SD, na.rm = TRUE)), .SDcols = -1]

來源

2017-02-06 15:19:17 Jaap

哈......我只是想查看如何在'do.call'中傳遞'na.rm' :) – Sotos

列組中最小的返回值

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