[R] Conditional extraction of values in a data.frame in r

[Marna Wagley]

Hi R Users,
I have been struggling to extract the data based on conditional values in
different columns. I have a very big dataset (rows) and a couple of
columns. here an example of the dataset is:

daT<-structure(list(ID = c("id1", "id2", "id3", "id4", "id5", "id6",

"id7"), First_detectiondate = c("7/21/2015", "5/19/2015", "5/27/2015",

NA, "9/25/2015", NA, NA), Second_detectiondate = c(NA, NA, "6/1/2015",

"5/29/2015", NA, NA, "4/17/2015"), third_detectiondate = c(NA,

"5/21/2015", "6/20/2015", NA, NA, "", NA)), class = "data.frame", row.names
= c(NA,

-7L))


head(daT)


I wanted to put conditions such as: if any of the columns of 2.3.4 has a
date, get the date which was latest. If there is no date, put NA. and I was
looking for the output as shown in the following table.


output<-structure(list(ID = c("id1", "id2", "id3", "id4", "id5", "id6",

"id7"), First_detectiondate = c("7/21/2015", "5/19/2015", "5/27/2015",

NA, "9/25/2015", NA, NA), Second_detectiondate = c(NA, NA, "6/1/2015",

"5/29/2015", NA, NA, "4/17/2015"), third_detectiondate = c(NA,

"5/21/2015", "6/20/2015", NA, NA, "", NA), output1 = c("7/21/2015",

"5/21/2015", "6/20/2015", "5/29/2015", "9/25/2015", NA, "4/17/2015"

)), class = "data.frame", row.names = c(NA, -7L))

head(output)



Is there a way to get the table similar to the table "output"?


Thank you very much for your help.


Sincerely,


MW

	[[alternative HTML version deleted]]