[R] MULTIPLE LEVELS for a SINGLE VALUE in a dataframe, how do I remove these?

Frede Aakmann Tøgersen frtog at vestas.com
Wed Apr 2 07:29:21 CEST 2014

Hi 'What is your name?'

When you read the data into R the first column was interpreted as a factor where the levels are the timestamps. If you used read.table() there is the stringsAsFactor you can set to FALSE so that the first column will be read in as strings instead of a factor.

However you can now do this.

antdist$ts <- as.character(antdist$ts)

antdist$ts <- as.POSIXct(strptime(antdist$ts, format = "%m/%d/%Y %H:%M:%S"))

See ?factor, ?as.POSIXct, ?strptime

Yours sincerely / Med venlig hilsen

Frede Aakmann Tøgersen
Specialist, M.Sc., Ph.D.
Plant Performance & Modeling

Technology & Service Solutions
T +45 9730 5135
M +45 2547 6050
frtog at vestas.com

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> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of elle
> Sent: 1. april 2014 20:35
> To: r-help at r-project.org
> Subject: [R] MULTIPLE LEVELS for a SINGLE VALUE in a dataframe, how do I
> remove these?
> I have a series of dates and times in one column.  They are all in the format
> "%m/%d/%Y %H:%M:%S"; however, they are character values.
> I have a number of problems:
> 1) if I use antdist$ts[1] to just examine the FIRST value of the timestamp
> (ts) column, it shows that there are 144873 Levels, and it should only have
> 1 Level with the first value of "6/1/2013 08:07:39"; how do I delete the
> remaining levels?
> 2) I need to change this column to a factor, so that I can use it in
> functions and graph it, etc.  It's useless in this format.  I think that
> once I can remove the levels, I can use as.Date or as.POSIXct to do this,
> but I need to figure out what's happening in the first part of the question.
> Here's the R code for just looking at the first value of the timestamp
> column:
> > antdist$ts[1]
> [1] 6/1/2013 08:07:39
> 144873 Levels: 6/1/2013 08:07:39 6/1/2013 08:07:41 6/1/2013 08:07:43
> 6/1/2013 08:07:45 ... 8/2/2013 11:47:51
> Here's a photo of what the first few rows of the timestamp column look like
> using View(antdist):
> <http://r.789695.n4.nabble.com/file/n4687977/Capture.jpg>
> Thank you, thank you, thank you for your help!
> --
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> LEVELS-for-a-SINGLE-VALUE-in-a-dataframe-how-do-I-remove-these-
> tp4687977.html
> Sent from the R help mailing list archive at Nabble.com.
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