On Aug 12, 2010, at 4:06 PM, Toby Gass wrote:
Thank you all for the quick responses. So far as I've checked,
Marc's solution works perfectly and is quite speedy. I'm still
trying to figure out what it is doing. :)
Henrique's solution seems to need some columns somewhere. David's
solution does not find all the other measurements, possibly with
positive values, taken on the same day.
I assumed you only wanted to look at what appeared to be a data
column, SLOPE. If you want to look at all columns for negatives then
try:
toy[ which( apply(toy, 1, function(x) all(x >= 0)) ), ] # or
toy[ apply(toy, 1, function(x) all(x >= 0)) , ]
This is how they differ w,r,t, their handling of NA's.
> toy[3,2] <- NA
> toy[ apply(toy, 1, function(x) all(x >= 0)) , ]
CH DAY SLOPE
1 3 4 0.2
2 4 4 0.3
NA NA NA NA
4 3 4 0.5
5 4 4 0.6
6 5 5 0.2
7 3 5 0.1
8 4 5 0.0
> toy[ which(apply(toy, 1, function(x) all(x >= 0)) ), ]
CH DAY SLOPE
1 3 4 0.2
2 4 4 0.3
4 3 4 0.5
5 4 4 0.6
6 5 5 0.2
7 3 5 0.1
8 4 5 0.0
Thank you again for your efforts.
Toby
On 12 Aug 2010 at 14:32, Marc Schwartz wrote:
On Aug 12, 2010, at 2:24 PM, Marc Schwartz wrote:
On Aug 12, 2010, at 2:11 PM, Toby Gass wrote:
Dear helpeRs,
I have a dataframe (14947 x 27) containing measurements collected
every 5 seconds at several different sampling locations. If one
measurement at a given location is less than zero on a given day, I
would like to delete all measurements from that location on that
day.
Here is a toy example:
toy <- data.frame(CH = rep(3:5,3), DAY = c(rep(4,5), rep(5,4)),
SLOPE = c(seq(0.2,0.6, .1),seq(0.2, -0.1, -0.1)))
In this example, row 9 has a negative measurement for Chamber 5,
so I
would like to delete row 6, which is the same Chamber on the same
day, but not row 3, which is the same chamber on a different
day. In
the full dataframe, there are, of course, many more days.
Is there a handy R way to do this?
Thank you for the assistance.
Toby
Not fully tested, but here is one possibility:
toy
CH DAY SLOPE
1 3 4 0.2
2 4 4 0.3
3 5 4 0.4
4 3 4 0.5
5 4 4 0.6
6 5 5 0.2
7 3 5 0.1
8 4 5 0.0
9 5 5 -0.1
subset(toy, ave(SLOPE, CH, DAY, FUN = function(x) any(x < 0)) == 0)
CH DAY SLOPE
1 3 4 0.2
2 4 4 0.3
3 5 4 0.4
4 3 4 0.5
5 4 4 0.6
7 3 5 0.1
8 4 5 0.0
This can actually be slightly shortened to:
subset(toy, !ave(SLOPE, CH, DAY, FUN = function(x) any(x < 0)))
CH DAY SLOPE
1 3 4 0.2
2 4 4 0.3
3 5 4 0.4
4 3 4 0.5
5 4 4 0.6
7 3 5 0.1
8 4 5 0.0
HTH,
Marc
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West Hartford, CT
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
