[R] Convert a column of numbers to a column of strings
Erik Iverson
eriki at ccbr.umn.edu
Mon Feb 1 20:15:11 CET 2010
Also, although you don't need it to accomplish what you want, you were
probably looking for the as.character function instead of toString...
Tam Le wrote:
> Hello,
>
> Please excuse me if this question has been asked before. I'm new to R, and
> have been trying to google the answers without any success.
>
> I would like to convert a set of date and time into R date-time class. Right
> now, the dates and times are in integer format, so I first need to convert
> them into string, and then to R date-time using strptime. However, I have a
> problem converting them from integer to string:
>
> data:
>
> Date Time
> 20091209 1200
> 20091209 1500
> 20091209 1800
> ....
> 20091210 800
> 20091210 1000
> 20091210 1600
> ....
>
> I used:
>
> tempdate=toString(Date)
> day=substr(tempdate, 7, 8)
> month=substr(tempdate, 5, 6)
> year=substr(tempdate, 1, 2)
> rDate=strptime(paste(year, month, day, sep="-"))
>
> the 1st command does not create a new column with string dates in it, it
> creates a single row that has all the dates in a single string, like this:
> "20091209, 20091209, .... 20091210, 20091210"
> "day" ends up being 1 number, 09, instead of a column of days. I ended up
> having all rDate=2009/12/09, which is the first row.
>
> Could you please tell me how to do this correctly?
>
> Thanks,
> Tam
>
>
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