Problem with strptime
Dates and times are notoriously tricky to get right and the fact that
the printed representation is so different from the internal (which is
basically just a count of seconds) doesn't really help: to make this
fully reproducible, could you supply us with the output of
dput(head(read.table("data1.txt",header=T,sep="\t"), 30))
dput(head(read.table("data2.txt",header=T,sep="\t"), 30))
as well?
Thanks!
Michael
On Sun, May 27, 2012 at 3:56 PM, Des Callaghan
<des.callaghan at ecostudy.co.uk> wrote:
Hello Forum, I have a problem with the strptime function. With the 'data1' dataset below it works fine, but with the 'data2' dataset something goes wrong (see final line below). Both data1 and data2 are in exactly the same original format, the only difference is that they span different dates. Please help, since it is driving me nuts! Many thanks. Best wishes, Des -
data1=read.table("data1.txt",header=T,sep="\t")
datetime1=strptime(data1$Date, "%a %b %d %H:%M:%S %Y") #example line from
data1 'Tue Aug 16 03:00:01 2011'
summary(datetime1)
? ? ? ? ? ? ? ? ? ? Min. ? ? ? ? ? ? ? ? ? 1st Qu. Median ? ? ? ? ? ? ? ? ? ? ?Mean "2011-08-15 21:00:01 BST" "2011-10-08 01:00:01 BST" "2011-11-30 05:00:01 GMT" "2011-11-30 04:38:47 GMT" ? ? ? ? ? ? ? ? ?3rd Qu. ? ? ? ? ? ? ? ? ? ? ?Max. "2012-01-22 09:00:01 GMT" "2012-03-15 13:00:01 GMT"
min(datetime1)
[1] "2011-08-15 21:00:01 BST"
data2=read.table("data2.txt",header=T,sep="\t")
datetime2=strptime(data2$Date, "%a %b %d %H:%M:%S %Y") #example line from
data2 'Sun Nov 27 13:07:01 2011'
summary(datetime2)
? ? ? ? ? ? ? ? ? ? Min. ? ? ? ? ? ? ? ? ? 1st Qu. Median ? ? ? ? ? ? ? ? ? ? ?Mean "2011-11-27 01:07:01 GMT" "2012-01-09 20:07:01 GMT" "2012-02-22 15:07:01 GMT" "2012-02-22 15:26:16 GMT" ? ? ? ? ? ? ? ? ?3rd Qu. ? ? ? ? ? ? ? ? ? ? ?Max. "2012-04-06 12:07:01 BST" "2012-05-20 07:07:01 BST"
min(datetime2)
[1] NA ? ? ? ?[[alternative HTML version deleted]]
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