This is large data set Spencer. What about when the dates change as below:
COL1 COL2 Jan-14 1-Aug-16 Feb-14 1-Aug-16 Mar-14 1-Aug-16 Apr-14 1-Aug-16 May-14 1-Aug-16 Jun-14 1-Aug-16 Jul-14 1-Aug-16 Aug-14 1-Aug-16 Sep-14 1-Aug-16 Oct-14 1-Aug-16 Nov-14 1-Aug-16 Dec-14 1-Aug-16 Jan-15 1-Aug-16 Feb-15 1-Aug-16 Mar-15 1-Aug-16 Apr-15 1-Aug-16 May-15 1-Aug-16 Jun-15 1-Aug-16 Jul-15 1-Aug-16 Aug-15 1-Aug-16 Sep-15 1-Aug-16 Oct-15 1-Aug-16 Nov-15 1-Aug-16 Dec-15 1-Aug-16 Jan-16 1-Aug-16 Feb-16 1-Aug-16 Mar-16 1-Aug-16 Apr-16 1-Aug-16 May-16 1-Aug-16 Jun-16 1-Aug-16 Jul-16 1-Aug-16 Aug-16 1-Aug-16 Sep-16 1-Aug-16 Oct-16 1-Aug-16 ________________________________ From: R-help <r-help-boun...@r-project.org> on behalf of Spencer Graves <spencer.gra...@effectivedefense.org> Sent: Tuesday, August 22, 2017 2:49 PM To: r-help@r-project.org Subject: Re: [R] Convert Factor to Date On 2017-08-22 1:30 PM, Patrick Casimir wrote: > Dear R Fellows, > > > I Have a dataset( data1) with 2 columns of date showing a class of factor. > How to convert them to date? Then compare them, keep the greater date only in > a new column. Using as.Date to change the class to Date but the data becomes > NA. When I specified a format with the second date, I got the desired behavior: > as.Date(factor('1-Nov-16'), '%d-%b-%y') [1] "2016-11-01" > as.Date('Nov-16', '%b-%y') [1] NA > as.Date(factor('Nov-16'), '%b-%y') [1] NA > as.Date('Nov-16', '%b-%y') [1] NA To convert the first column, I pasted "1-" in front: as.Date(paste0('1-', factor('Nov-16')), '%d-%b-%y') Hope this helps. Spencer > Much Thanks > > > COL1 COL2 > Apr-16 1-Nov-16 > May-16 1-Nov-16 > Jun-16 1-Nov-16 > Jul-16 1-Nov-16 > Aug-16 1-Nov-16 > Sep-16 1-Nov-16 > Oct-16 1-Nov-16 > Nov-16 1-Nov-16 > Dec-16 1-Nov-16 > Jan-17 1-Nov-16 > Feb-17 1-Nov-16 > Mar-17 1-Nov-16 > Apr-17 1-Nov-16 > May-17 1-Nov-16 > Jun-17 1-Nov-16 > Jul-17 1-Nov-16 > Aug-17 1-Nov-16 > Sep-17 1-Nov-16 > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=02%7C01%7Cpatrcasi%40nova.edu%7C6abf3517ab5f407427d308d4e98e9efd%7C2c2b2d312e3e4df1b571fb37c042ff1b%7C0%7C0%7C636390246143633480&sdata=jwTeb%2BvH0bbkXdckgzE6PJZ3gDl9d1%2F3t9K%2BxDtjyls%3D&reserved=0 > PLEASE do read the posting guide > https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.R-project.org%2Fposting-guide.html&data=02%7C01%7Cpatrcasi%40nova.edu%7C6abf3517ab5f407427d308d4e98e9efd%7C2c2b2d312e3e4df1b571fb37c042ff1b%7C0%7C0%7C636390246143633480&sdata=GUAR582xxtA88KLkQC1oPnvyNecfUyXjV9MrIziJicU%3D&reserved=0 > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=02%7C01%7Cpatrcasi%40nova.edu%7C6abf3517ab5f407427d308d4e98e9efd%7C2c2b2d312e3e4df1b571fb37c042ff1b%7C0%7C0%7C636390246143633480&sdata=jwTeb%2BvH0bbkXdckgzE6PJZ3gDl9d1%2F3t9K%2BxDtjyls%3D&reserved=0 PLEASE do read the posting guide https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.R-project.org%2Fposting-guide.html&data=02%7C01%7Cpatrcasi%40nova.edu%7C6abf3517ab5f407427d308d4e98e9efd%7C2c2b2d312e3e4df1b571fb37c042ff1b%7C0%7C0%7C636390246143633480&sdata=GUAR582xxtA88KLkQC1oPnvyNecfUyXjV9MrIziJicU%3D&reserved=0 and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.