Displaying 7 results from an estimated 7 matches for "isfirstinrun".
2012 Oct 16
5
uniq -c
I need an analogue of "uniq -c" for a data frame.
xtabs(), although dog slow, would have footed the bill nicely:
--8<---------------cut here---------------start------------->8---
> x <- data.frame(a=1:32,b=1:32,c=1:32,d=1:32,e=1:32)
> system.time(subset(as.data.frame(xtabs( ~. , x )), Freq != 0 ))
user system elapsed
12.788 4.288 17.224
--8<---------------cut
2009 Mar 12
4
who can give me some hint?
Hi All,
> act_2
Date Dtime Hour Min Second Rep
51 2006-02-22 14:52:18 14 52 18 useractivity_act
52 2006-02-22 14:52:18 14 52 18 4
55 2006-02-22 14:52:49 14 52 49 4
57 2006-02-22 14:52:51 14 52 51 4
58 2006-02-22 14:52:52 14 52 52 3
60 2006-02-22 14:54:42 14 54
2010 Apr 22
4
how to select the first observation only?
Dear r-helpers,
I have a very simple question. Suppose my data is like
id=c(rep(1,2),rep(2,2))
b=c(2,3,4,5)
m=cbind(id,b)
> m
id b
[1,] 1 2
[2,] 1 3
[3,] 2 4
[4,] 2 5
I wish to select the first observation for each id. That is, I want to
quickly select two rows:
id b
1 2
2 4
only. how should i do this?
[[alternative HTML version deleted]]
2010 Jan 27
3
Function for describing segements in sequential data
Dear R-users,
Say that I have a sequence of zeroes and ones:
x <- c(1,1,1,0,0,0,0,1,1,1,0,0,0,0,1,1,1,0,0,0,0)
The sequences of ones represent segments and I want to report the starting and endpoints of these segments. For example, in 'x', the first segment starts at location 1 and ends at 3, and the second segment starts at location 8 and ends at location 10. Is there an efficient
2009 Oct 02
6
split-apply question
Hi,
I have a data frame that looks like this:
>x
x1 x2 x3
A 1 1.5
B 2 0.9
B 3 2.7
C 7 1.8
D 7 1.3
I want to "group" by the x1 column and in the case of multiple x$x1 values
(e.g., "B")d, return rows that have the smallest values of x2. In the case
of rows with only one value of x1 (e.g., "A"), return the row as is. How can
I do that?
2011 Aug 31
1
formatting a 6 million row data set; creating a censoring variable
List,
Consider the following data.
gender mygroup id
1 F A 1
2 F B 2
3 F B 2
4 F B 2
5 F C 2
6 F C 2
7 F C 2
8 F D 2
9 F D 2
10 F D 2
11 F D 2
12 F D 2
13 F D 2
14 M A 3
15 M A 3
16 M A 3
17
2009 Feb 27
3
Making tapply code more efficient
Previously, I posed the question pasted down below to the list and
received some very helpful responses. While the code suggestions
provided in response indeed work, they seem to only work with *very*
small data sets and so I wanted to follow up and see if anyone had ideas
for better efficiency. I was quite embarrased on this as our SAS
programmers cranked out programs that did this in the blink