在R中使用as.Date轉換爲日期並獲取一系列「NA」s

Question

使用以下代碼嘗試將我的日期列轉換爲正確格式，但它只是將所有日期返回爲「NA」。

setwd("C:\\Users\\user\\Documents\\Files\\a") 
data <- read.csv("file1.csv") 

data$Date <- as.Date(data$Date, format = "d%/m%/Y%") 

編輯：日期值如下：11/09/2009

Answer 1

從?as.Date文檔：

If the date string does not specify the date completely, the returned answer may be system-specific. The most common behaviour is to assume that a missing year, month or day is the current one. If it specifies a date incorrectly, reliable implementations will give an error and the date is reported as ‘NA’. Unfortunately some common implementations (such as ‘glibc’) are unreliable and guess at the intended meaning.

data$Date <- as.Date(data$Date, format = "%d/%m/%Y") 

Answer 2

你可以嘗試用包lubridate轉換日期

library(lubridate) 
date <- parse_date_time(x = date, 
       orders = c("d m y", "d B Y", "mdy"), 
       locale = "eng") 

後，你可以指定你想要的日期是哪一種格式：

character_date <- as.character(as.Date(date, "%m/%d/%Y"), format = "%m/%d/%Y")