Dates in Common

I have two collections of dates and I want to figure out what dates they have
in common. This is not giving me what I want (I don't know what it is giving
me). What is the best way to do this?

Tom
data1
[1] "1948-02-24 EST" "1949-04-12 EST" "1950-05-29 EDT" "1951-05-21 EDT"
 [5] "1951-12-20 EST" "1953-01-22 EST" "1955-02-28 EST" "1956-03-08 EST"
 [9] "1957-03-22 EST" "1958-02-07 EST"
data2
[1] "1948-02-24 EST" "1949-04-12 EST" "1950-05-29 EDT" "1951-05-21 EDT"
 [5] "1951-12-20 EST" "1953-01-22 EST" "1955-02-28 EST" "1956-03-08 EST"
 [9] "1957-03-22 EST" "1958-02-07 EST"
intersect(data1,data2)
[1] -689626800 -653943600 -618350400 -587505600 -569098800 -534625200
 [7] -468356400 -436042800 -403297200 -375476400
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you want:
ans <- intersect(data1,data2)
class(ans) <- c("POSIXt","POSIXct")

I personally think intersect should preserve the class of the object
(if both args have the same class), but I think r-core has a different
opinion.

-Whit
I have two collections of dates and I want to figure out what dates they have
in common. This is not giving me what I want (I don't know what it is giving
me). What is the best way to do this?

Tom

data1
 [1] "1948-02-24 EST" "1949-04-12 EST" "1950-05-29 EDT" "1951-05-21 EDT"
 [5] "1951-12-20 EST" "1953-01-22 EST" "1955-02-28 EST" "1956-03-08 EST"
 [9] "1957-03-22 EST" "1958-02-07 EST"
data2
 [1] "1948-02-24 EST" "1949-04-12 EST" "1950-05-29 EDT" "1951-05-21 EDT"
 [5] "1951-12-20 EST" "1953-01-22 EST" "1955-02-28 EST" "1956-03-08 EST"
 [9] "1957-03-22 EST" "1958-02-07 EST"
intersect(data1,data2)
 [1] -689626800 -653943600 -618350400 -587505600 -569098800 -534625200
 [7] -468356400 -436042800 -403297200 -375476400
--
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The problem is in the intersect function that does x = as.vector(x) and 
therefore transforms date vector into a numeric .
Try to:
 d1 = as.character(data1) ; d2 = as.character(data2)
 d = intersect(d1, d2)
 data = as.Date(d)

A.
I have two collections of dates and I want to figure out what dates they have
in common. This is not giving me what I want (I don't know what it is giving
me). What is the best way to do this?

Tom

data1

 [1] "1948-02-24 EST" "1949-04-12 EST" "1950-05-29 EDT" "1951-05-21 EDT"
 [5] "1951-12-20 EST" "1953-01-22 EST" "1955-02-28 EST" "1956-03-08 EST"
 [9] "1957-03-22 EST" "1958-02-07 EST"

data2

 [1] "1948-02-24 EST" "1949-04-12 EST" "1950-05-29 EDT" "1951-05-21 EDT"
 [5] "1951-12-20 EST" "1953-01-22 EST" "1955-02-28 EST" "1956-03-08 EST"
 [9] "1957-03-22 EST" "1958-02-07 EST"

intersect(data1,data2)

 [1] -689626800 -653943600 -618350400 -587505600 -569098800 -534625200
 [7] -468356400 -436042800 -403297200 -375476400