> On Mar 13, 2017, at 5:53 PM, Val <valkr...@gmail.com> wrote:
>
> HI all,
>
> if first name is Alex then I want concatenate the second column to Alex
> to produce Alex and the second column value
>
> DF1 <- read.table(header=TRUE, text='first YR
> Alex 2001
> Bob 2001
> Cory 2001
> Cory 2002
> Bob 2002
> Bob 2003
> Alex 2002
> Alex 2003
> Alex 2004')
>
>
> Output
> data frame
> DF2
> Alex-2001 2001
> Bob 2001
> Cory 2001
> Cory 2002
> Bob 2002
> Bob 2003
> Alex-2002 2002
> Alex-2003 2003
> Alex-2004 2004
>
> I tried this one but did not work.
> DF1$first[DF1$first=="Alex"] <- paste(DF1$first, DF1$YR, sep='-')
>
> Thank you in advance
Hi,
See ?ifelse and try this:
DF1$Comb <- ifelse(DF1$first == "Alex",
paste(DF1$first, DF1$YR, sep = "-"),
as.character(DF1$first))
> DF1
first YR Comb
1 Alex 2001 Alex-2001
2 Bob 2001 Bob
3 Cory 2001 Cory
4 Cory 2002 Cory
5 Bob 2002 Bob
6 Bob 2003 Bob
7 Alex 2002 Alex-2002
8 Alex 2003 Alex-2003
9 Alex 2004 Alex-2004
Note the coercion of the second returned value to character, otherwise you get
the numeric code associated with the factor levels of DF1$first.
I generally try to avoid overwriting the source data, or in this case, column,
to preserve it for future use as may be needed.
Regards,
Marc Schwartz
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