[R] Comparing 2 dale columns

Wed Aug 23 18:56:14 CEST 2017

: Thanks. But when I apply your codes I get all NA instead of TRUE and FALSE

You need to show a self-contained example of your problem, one that others
can copy and paste into their R sessions.  E.g.,

data <- read.table(header=TRUE, stringsAsFactors=FALSE, text="
COL1       COL2
6/1/14     5/1/15
7/1/14     5/1/15")
data$COL1<- as.Date(data$COL1, format="%d/%m/%y")
data$COL2<- as.Date(data$COL2, format="%d/%m/%y")
str(data)
#'data.frame':   2 obs. of  2 variables:
# $ COL1: Date, format: "2014-01-06" "2014-01-07"
# $ COL2: Date, format: "2015-01-05" "2015-01-05"
transform(data, `Col2>Col1` = COL2 > COL1, `Col2-Col1` = COL2 - COL1,
check.names=FALSE)
#        COL1       COL2 Col2>Col1 Col2-Col1
#1 2014-01-06 2015-01-05      TRUE  364 days
#2 2014-01-07 2015-01-05      TRUE  363 days

Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, Aug 23, 2017 at 9:09 AM, Patrick Casimir <patrcasi at nova.edu> wrote:

>
> Thanks. But when I apply your codes I get all NA instead of TRUE and FALSE
>
> ________________________________
> From: PIKAL Petr <petr.pikal at precheza.cz>
> Sent: Wednesday, August 23, 2017 11:20:00 AM
> To: Patrick Casimir; r-help at r-project.org
> Subject: RE: Comparing 2 dale columns
>
> Hi
>
> your code is wrong.
>
> I get
> > test<-read.table("clipboard", header=T)
> > str(test)
> 'data.frame':   2 obs. of  2 variables:
>  $ COL1: Factor w/ 2 levels "6/1/14","7/1/14": 1 2
>  $ COL2: Factor w/ 1 level "5/1/15": 1 1
> > test$COL2<- as.Date(as.character(test$COL2, format="%y/%m/%d"))
> > test$COL1<- as.Date(as.character(test$COL1, format="%y/%m/%d"))
>
>        ^^^^^^^^^^^^^^^^^^^^^^^
> incorrect parentheses position, wrong y,m,d
>
> Using correct syntax I get correct result.
>
> > test$COL2<- as.Date(test$COL2, format="%d/%m/%y")
> > test$COL1<- as.Date(test$COL1, format="%d/%m/%y")
> >
> > test$COL2 > test$COL1
> [1] TRUE TRUE
> > test
>         COL1       COL2
> 1 2014-01-06 2015-01-05
> 2 2014-01-07 2015-01-05
> >
>
> Cheers
> Petr
>
> > -----Original Message-----
> > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Patrick
> > Casimir
> > Sent: Wednesday, August 23, 2017 4:54 PM
> > To: r-help at r-project.org
> > Subject: [R] Comparing 2 dale columns
> >
> > Dear R fellows,
> >
> >
> > I created a new column Date_flag to compare the dates of COL1 and COL2
> > using the code below. But it showed that 5/1/15 is greater than 6/1/2014
> and
> > 5/1/2015 greater than
> > 7/1/2014 despite the year is greater. How do I fix that? I did try to
> format as
> > %y/%m/%d
> >
> >  but it does not fix that.
> >
> >
> > data$Date_Flag <- ifelse(data$COL2 > data$COL1, 0,1)
> >
> >
> > COL1       COL2
> > 6/1/14     5/1/15
> > 7/1/14     5/1/15
> >
> >
> > data$COL2<- as.Date(as.character(data$COL2, format="%y/%m/%d"))
> > data$COL1<- as.Date(as.character(data$COL1, format="%y/%m/%d"))
> >
> >
> >       [[alternative HTML version deleted]]
> >
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