[R] How to Transform a Factor Variable into a Date
David L Carlson
dcarlson at tamu.edu
Mon Jun 19 22:06:00 CEST 2017
The R list does not recognize .csv files so your attachment got stripped. It is picky that way. Tacking .txt to the end might trick it into preserving the attachment.
Dataset <- read.table()
created a data.frame called Dataset so the second command was redundant. Probably better would be read.csv() which automatically uses "," as the separator. Also including the argument as.is=TRUE will prevent conversion of character fields to factors. Then your conversion to dates should work once you add a day to the month-year format (e.g. first of the month or middle of the month):
> Test <- read.csv(text='"TransitDate", "CargoTons"
+ "Apr-2013", 50
+ "Jun-2013", 40
+ "Jul-2013", 30', as.is=TRUE)
> Test$TransitDate <- as.Date(paste0("01-", Test$TransitDate), "%d-%b-%Y")
'data.frame': 3 obs. of 2 variables:
$ TransitDate: Date, format: "2013-04-01" "2013-06-01" ...
$ CargoTons : int 50 40 30
1 2013-04-01 50
2 2013-06-01 40
3 2013-07-01 30
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Paul Bernal
Sent: Monday, June 19, 2017 2:07 PM
To: r-help at r-project.org
Subject: [R] How to Transform a Factor Variable into a Date
Hope you are doing great. I have a .csv file that I read into R, the .csv
file consistss of two fields (TransitDate and CargoTons).
The TransitDate I formatted from Excel in the fashion mmm-yy (e.g.:
Apr-2013). However R does not recognize the field TransitDate as a date
Here is the code:
Dataset <- read.table("U:/NEWCargoData.csv", header=TRUE, sep=",",
na.strings="NA", dec=".", strip.white=TRUE)
DatasetFrame <- data.frame(Dataset)
DatasetFrame$TransitDate <- as.Date(DatasetFrame$TransitDate, format =
Now, when I do DatasetFrame[1,1], the following happens:
Now when I do:
> Dataset[1,1] #this is the dataset as was read from my computer
62 Levels: Apr-13 Apr-14 Apr-15 Apr-16 Apr-17 Aug-13 Aug-14 Aug-15 Aug-16
Dec-12 Dec-13 Dec-14 ... Sep-16
I am also attaching the .csv file for your reference. How can I do to get R
to convert TransitDate into an actual date field? R is not recognizing it
as a date.
Any help will be greatly appreciated,
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