在read.table / read.csv中為colClasses參數指定自定義日期格式題：有沒有辦法在read.table / read.csv中使用colClasses參數時指定Date格式？（我意識到我可以在導入后進行轉換，但是有很多這樣的日期列，在導入步驟中更容易實現）例：我有一個.csv格式的日期列%d/%m/%Y。dataImport <- read.csv("data.csv", colClasses = c("factor","factor","Date"))這會導致轉換錯誤。例如，15/07/2008成為0015-07-20?？芍噩F的代碼：data <- structure(list(func_loc = structure(c(1L, 2L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 5L), .Label = c("3076WAG0003", "3076WAG0004", "3076WAG0007", "3076WAG0009", "3076WAG0010"), class = "factor"), order_type = structure(c(3L, 3L, 1L, 1L, 1L, 1L, 2L, 2L, 3L, 1L), .Label = c("PM01", "PM02", "PM03"), class = "factor"), actual_finish = structure(c(4L, 6L, 1L, 2L, 3L, 7L, 1L, 8L, 1L, 5L), .Label = c("", "11/03/2008", "14/08/2008", "15/07/2008", "17/03/2008", "19/01/2009", "22/09/2008", "6/09/2007"), class = "factor")), .Names = c("func_loc", "order_type", "actual_finish"), row.names = c(NA, 10L), class = "data.frame")write.csv(data,"data.csv", row.names = F) dataImport <- read.csv("data.csv")str(dataImport)dataImportdataImport <- read.csv("data.csv", colClasses = c("factor","factor","Date"))str(dataImport)dataImport
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楊__羊羊
TA貢獻1943條經驗 獲得超7個贊
如果您只想更改1種日期格式，則可以使用該Defaults軟件包更改其中的默認格式as.Date.character
library(Defaults)
setDefaults('as.Date.character', format = '%d/%M/%Y')
dataImport <- read.csv("data.csv", colClasses = c("factor","factor","Date"))
str(dataImport)
## 'data.frame': 10 obs. of 3 variables:
## $ func_loc : Factor w/ 5 levels "3076WAG0003",..: 1 2 3 3 3 3 3 4 4 5
## $ order_type : Factor w/ 3 levels "PM01","PM02",..: 3 3 1 1 1 1 2 2 3 1
## $ actual_finish: Date, format: "2008-10-15" "2009-10-19" NA "2008-10-11" ...
我認為@Greg Snow的答案要好得多，因為它不會改變常用函數的默認行為。
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