Question

So I have data that is in 1 minute resolution. Suppose I’d only like to sample every point in my subset 1 minute past the hour (e.g. 9:01, 10:01…). How would I go about doing that? I tried playing around with endpoints, but it doesn’t seem possible.

edit:

AUD_CAD AUD_CHF AUD_JPY AUD_NZD AUD_USD AUX_AUD BCO_USD CAD_CHF CAD_JPY CHF_JPY ETX_EUR EUR_AUD EUR_CAD EUR_CHF EUR_CZK EUR_DKK EUR_GBP EUR_HUF  EUR_JPY EUR_NOK
2012-09-30 17:01:00 1.020020 0.97523  80.827 1.25020 1.03652      NA      NA 0.95623  79.241 82.8625      NA 1.23938 1.26419 1.20882      NA 7.45529 0.79569 285.598 100.1815 7.36363

Here’s an example of the data

Answer 1

## An example xts object with data pts at each minute in the past 12 hours
library(xts)
times <- seq(Sys.time() - 12*60*60, Sys.time(), by="min")
x <- xts(index(times), times)

## Extract only those occuring at one minute past an hour.
x[strftime(index(x), format="%M") == "01"]
#                     [,1]
# 2012-11-18 23:01:41    4
# 2012-11-19 00:01:41   64
# 2012-11-19 01:01:41  124
# 2012-11-19 02:01:41  184
# 2012-11-19 03:01:41  244
# 2012-11-19 04:01:41  304
# 2012-11-19 05:01:41  364
# 2012-11-19 06:01:41  424
# 2012-11-19 07:01:41  484
# 2012-11-19 08:01:41  544
# 2012-11-19 09:01:41  604
# 2012-11-19 10:01:41  664