[英]Using R to convert factor to date
我知道這個問題已被反復詢問,道歉,但我只是看不到錯誤...試圖將一個因素轉換為如下的日期,無論我嘗試過什么,我仍然得到N / A.
> class(cd$StartDate)
[1] "factor"
> head(cd)
StartDate Phase Cancer
1 Dec-89 Phase 2 breast
2 Jul-89 Phase 2 breast
3 Sep-92 Phase 1 breast
> cd$dates <- as.Date(cd$StartDate, format = "%b-%y)
> head(cd)
StartDate Phase Cancer dates
1 Dec-89 Phase 2 breast <NA>
2 Jul-89 Phase 2 breast <NA>
3 Sep-92 Phase 1 breast <NA>
我認為您需要為轉換工作提供一天的值:
cd$dates <- as.Date(
paste0(as.character(cd$StartDate), "-01"),
format = "%b-%y-%d")
##
R> str(cd)
#'data.frame': 3 obs. of 4 variables:
#$ StartDate: Factor w/ 3 levels "Dec-89","Jul-89",..: 1 2 3
#$ Phase : chr "Phase_2" "Phase_2" "Phase_1"
#$ Cancer : chr "breast" "breast" "breast"
#$ dates : Date, format: "1989-12-01" "1989-07-01" "1992-09-01"
數據:
cd <- read.table(
text = " StartDate Phase Cancer
1 Dec-89 Phase_2 breast
2 Jul-89 Phase_2 breast
3 Sep-92 Phase_1 breast",
header = TRUE,
stringsAsFactors = FALSE)
##
cd$StartDate <- as.factor(cd$StartDate)
我也嘗試過:
as.Date(as.character(cd$StartDate),format = "%m/%d/%y")
但低於一個工作
a<-as.character(cd$StartDate)
b<-as.Date.character(a, format = "%m/%d/%Y")
b
大寫字母中的Y
形式與眾不同。
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