Hi > > Dear all > I have a 'character' vector containing mixed formats (thanks Excel!) > and I'd like to translate it into a default "%Y-%m-%d" Date vector. > x <- c("1/3/2005", "13/04/2004", "2/5/2005", "2/5/2005", "7/5/2007", > "22/04/2004", "21/04/2005", "20080430", "13/05/2003", "20080529", > NA, NA, "19/05/1999", "17/05/2000", "17/05/2000") > > > In the above you will see that some dates are of format="%d/%m/%Y", > others of format="%Y%m%d" and some NA values. Can you suggest a > straight-forward way of transforming these to a uniform 'character' or > 'Date' vector? I tried to do the following, but it outputs very > strange results: > > x > [1] "1/3/2005" "13/04/2004" "2/5/2005" "2/5/2005" "7/5/2007" > "22/04/2004" > [7] "21/04/2005" "20080430" "13/05/2003" "20080529" NA > NA > [13] "19/05/1999" "17/05/2000" "17/05/2000" > > sum(xa <- grepl('/', x)) > [1] 11 > > sum(xb <- grepl('200', substr(x, 1,4))) > [1] 2 > > sum(xc <- is.na(x)) > [1] 2 > > x[xa] <- as.Date(x[xa], format="%d/%m/%Y") > > x[xb] <- as.Date(x[xb], format="%Y%m%d") > > x > [1] "12843" "12521" "12905" "12905" "13640" "12530" "12894" "13999" > "12185" "14028" > [11] NA NA "10730" "11094" "11094" >
You can use another as.Date with origin specified. as.Date(ifelse(ind, as.Date(x, format="%d/%m/%Y"), as.Date(x, format="%Y%m%d")) , origin="1970-01-01") [1] "2005-03-01" "2004-04-13" "2005-05-02" "2005-05-02" "2007-05-07" [6] "2004-04-22" "2005-04-21" "2008-04-30" "2003-05-13" "2008-05-29" [11] NA NA "1999-05-19" "2000-05-17" "2000-05-17" Regards Petr > > The culprit is likely that the 'x' vector is 'character' throughout, > but I'm not sure how to work around. For example, I couldn't figure > how to create an empty 'Date' vector. Regards > Liviu > > > -- > Do you know how to read? > http://www.alienetworks.com/srtest.cfm > http://goodies.xfce.org/projects/applications/xfce4-dict#speed-reader > Do you know how to write? > http://garbl.home.comcast.net/~garbl/stylemanual/e.htm#e-mail > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.