Displaying 20 results from an estimated 9000 matches similar to: "looping through predictors"
2010 May 05
1
randomForest: predictor importance (for regressions)
I have a question about predictor importances in randomForest.
Once I've run randomForest and got my object, I get their importances:
rfresult$importance
I also get the "standard errors" of the permutation-based importance
measure: rfresult$importanceSD
I have 2 questions:
1. Because I am dealing with regressions, I am getting an importance object
(rfresult$importance) with two
2009 Oct 13
4
replacing period with a space
Dear R-ers!
I have x as a variable in a data frame x.
x<-data.frame(x=c("aa.bb","cc.dd.ee"))
x$x<-as.character(x$x)
x
I am sorry for such a simple question - but how can I replace all
periods in x$x with spaces?
sub('.', ' ', x$x) - removes all letters to the left of each period...
Thanks a lot for your advice!
--
Dimitri Liakhovitski
Ninah.com
2009 Sep 17
2
referring to a row number and to a row condition, and to columns simultaneously
Hello, dear R-ers!
I have a data frame:
x<-data.frame(a=c(4,2,4,1,3,4),b=c(1,3,4,1,5,0),c=c(NA,2,5,3,4,NA),d=rep(NA,6),e=rep(NA,6))
x
When x$a==1, I would like to replace NAs in columns d and e with 8 and
9, respectively
When x$a != 1, I would like to replace NAs in columns d and e 101 and
1022, respectively.
However, I only want to do it for rows 2:5 - while ignoring what's
happening in
2010 Mar 30
4
Code is too slow: mean-centering variables in a data frame by subgroup
Dear R-ers,
I have a large data frame (several thousands of rows and about 2.5
thousand columns). One variable ("group") is a grouping variable with
over 30 levels. And I have a lot of NAs.
For each variable, I need to divide each value by variable mean - by
subgroup. I have the code but it's way too slow - takes me about 1.5
hours.
Below is a data example and my code that is too
2009 Sep 21
5
More elegant way of excluding rows with equal values in any 2 columns?
Hello, dear R-ers!
I built a data frame "grid" (below) with 4 columns. I want to exclude
all rows that have equal values in ANY 2 columns. Here is how I am
doing it:
index<-expand.grid(1:4,1:4,1:4,1:4)
dim(index)
# Deleting rows that have identical values in any two columns (1 line of code):
2009 Sep 04
2
transforming a badly organized data base into a list of data frames
Dear R-ers!
I have a badly organized data base in Excel. Once I read it into R it
looks like this (all variables become factors because of many spaces
and other characters in Excel):
2010 Oct 26
1
lme vs. lmer results
Hello,
and sorry for asking a question without the data - hope it can still
be answered:
I've run two things on the same data:
# Using lme:
mix.lme <- lme(DV ~a+b+c+d+e+f+h+i, random = random = ~ e+f+h+i|
group, data = mydata)
# Using lmer
mix.lmer <- lmer(DV
~a+b+c+d+(1|group)+(e|group)+(f|group)+(h|group)+(i|group), data =
mydata)
lme provided an output (fixed effects and random
2011 Jan 13
1
setting up a genoud run
Hello - and sorry for a possibly stupid question, I'm just starting to
learn rgenoud.
I am defining a function with 5 parameters (p1, p2, p3, p4a, and p4b)
and then want to optimize it using genoud. But I am doing something
wrong.
Before genoud is even able to run it says: "Error in p2 + 1.2 : 'p2'
is missing".
I assume I did not specify it right. My code is below.
The task
2010 Oct 01
3
Suppressing printing in the function
Hello!
I wrote a function that returns a data frame. Nowhere in the function
do I say print(my.data.frame), but when I run the function - the data
frame is printed on the console.
Is there any way to suppress it?
Thank you!
--
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com
2009 Sep 23
2
Function to check if a vector contains a given value?
Dear R'rs,
is there a function that checks if a given vector contains a certain value.
E.g., x<-c(1,2,3,4).
How can I get a TRUE or FALSE for whether x contains a 2?
--
Dimitri Liakhovitski
Ninah.com
Dimitri.Liakhovitski at ninah.com
2010 Mar 18
1
R takes long time to open
Hello.
Until today I've been using R2.9 and since today R2.10 (on a PC).
In both of them it takes about 20 sec for the prompt to appear IN R
console after I start R. And every time it says: "Previous saved work
space restored" - even if I have not saved any workspace or, in case
of R2.10 - even though I have not used it once.
In the older versions - R would start within 2-3 sec.
Is
2010 Mar 04
4
Analogue to SPSS regression commands ENTER and REMOVE in R?
I am not sure if this question has been asked before - but is there a
procedure in R (in lm or glm?) that is equivalent to ENTER and REMOVE
regression commands in SPSS?
Thanks a lot!
--
Dimitri Liakhovitski
Ninah.com
Dimitri.Liakhovitski at ninah.com
2011 Feb 25
6
preventing repeat in "paste"
Hello!
s<-"start"; e<-"end"
middle<-as.character(c(1,2,3))
I would like to get the following result:
"start 123 end" or "start 1 2 3 end" or "start 1,2,3 end"
How can I avoide this (undesired) result:
paste(s,middle,e,sep=" ")
Thank you!
--
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com
2010 Oct 25
3
finding the year of a date
I know that I can use as.yearmon in the package "zoo" to find the year
and the month of a date.
I can use as. yearqtr to find the year and the quarter.
But how can one find just the year of a date?
Thanks a lot!
--
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com
2010 May 08
1
Increasing the font size on axes in trellis
Hello,
the code below gives me the picture I need - but there is on small
thing I can't figure out.
The plot has very small tick mark labels for both axes. I don't mean
the axis labels - they are both good, but what is shown near the tick
marks.
Please help me figure out what parameter I should add to make those
larger. I tried sticking cex.lab=1.3 in different places but it didn't
2010 Sep 27
1
stacked area chart
Dear R-ers!
Asking for your help with building the stacked area chart for the
following simple data (several variables - with date on the X axis):
### Creating a data set
my.data<-data.frame(date=c(20080301,20080402,20080503,20090301,20090402,20090503,20100301,20100402,20100503),
x=c(1.1,1.0,1.6,1,2,1.5,2.1,1.3,1.9),y=c(-4,-3,-6,-5,-7,-5.2,-6,-4,-4.9),
2010 Aug 13
3
transforming dates into years
Hello!
If I have in my data frame MyFrame a variable saved as a Date and want
to translate it into years, I currently do it like this using "zoo":
library(zoo)
as.year <- function(x) as.numeric(floor(as.yearmon(x)))
myFrame$year<-as.year(myFrame$date)
Is there a function that would do it directly - like "as.yearmon" -
but for years?
Thank you!
--
Dimitri
2011 Mar 30
3
optim and optimize are not finding the right parameter
Dear all,
I have a function that predicts DV based on one predictor pred:
pred<-c(0,3000000,7800000,15600000,23400000,131200000)
DV<-c(0,500,1000,1400,1700,1900)
## I define Function 1 that computes the predicted value based on pred
values and parameters a and b:
calc_DV_pred <- function(a,b) {
DV_pred <- rep(0,(length(pred)))
for(i in 1:length(DV_pred)){
DV_pred[i] <- a *
2011 Feb 03
1
rgenoud for multiple chips: does a more recent special version of "snow" exist?
Dear everyone,
I am trying to run rgenoud on several chips simultaneusly. I used the
instructions provided on Jasjeet Sekhon's Homepage
(http://sekhon.berkeley.edu/rgenoud/multiple_cpus.html).
However, I have the newer version of R (R 2.12) installed - for a
64-bit machine. So, when I tried to install the special version of
"snow" from a zip file provided by Jasjeet on his page, R
2010 Oct 29
1
help pages do not open
I have just installed R 12.
I have Windows 7, 64-bit verison.
I currently have IE as my default browser. The internet connection is very good.
Whenever I try to run a help command (?lm, for example), I get this error:
Error in shell.exec(url) : access to
'http://127.0.0.1:20271/library/stats/html/lm.html' denied
I first got this message when Google Chrome was my default browser.
For some