Displaying 20 results from an estimated 300 matches similar to: "Conditional merging in R & if then statement"
2012 Aug 29
2
Deduping in R by multiple variables
I have a dataset w/ 184K obs & 16 variables. In SAS I proc sort nodupkey it
in seconds by 11 variables.
I tried to do the same thing in R using both the unique & then the
!duplicated functions but it just hangs there & I get no output. Does
anyone know how to solve this?
This is how I tried to do it in R:
detail3 <-
2007 Jul 17
1
fit a nonlinear model using nlm()
I am trying to fit a nonlinear model using nlm().
My application of nlm() is a bit complicated.
Here is the story behind the model being fit:
The observer is trying to detect a signal corrupted by noise.
On each trial, the observer gets stim=signal+rnorm().
In the simulation below I have 500 trials. Each row of stim is a new trial.
On each trial, if the cross-correlation between the stim and
the
2012 Dec 02
1
Repeated-measures anova with a within-subject covariate (or varying slopes random-effects?)
Dear all,
I am having quite a hard time in trying to figure out how to correctly
spell out a model in R (a repeated-measures anova with a
within-subject covariate, I guess). Even though I have read in the
posting guide that statistical advice may or may not get an answer on
this list, I decided to try it anyway, hoping not to incur in
somebody's ire for misusing the tool.
For the sake of
2011 Feb 16
1
read.table - reading text variables as text
Hi
I'm reading a CSV file using read.table, and it keeps importing a text
variable as a factor. To overcome this, I've used the as.is command
referring to the variable in question (called "stim")
data<-read.table(file.choose(), header=T, sep=",", as.is = "stim")
However, "stim" is still imported as a factor. I notice there are other
read.table
2009 Dec 08
4
lower.tail option in pnorm
Hi,
I would have thought that these two constructions would
produce the same result but they do not.
Resp <- rbinom(10, 1, 0.5)
Stim <- rep(0:1, 5)
mm <- model.matrix(~ Stim)
Xb <- mm %*% c(0, 1)
ifelse(Resp, log(pnorm(Xb)), log(1 - pnorm(Xb)))
pnorm(as.vector(Xb), lower.tail = Resp, log.p = TRUE)
> ifelse(Resp, log(pnorm(Xb)), log(1 - pnorm(Xb)))
[1] -0.6931472 -1.8410216
2012 Oct 10
3
How to replicate SAS by group processing in R
Hello,
I am trying to re-code all my programs from SAS into R.
In SAS I use the following code:
proc sort data=upper;
by tdate stock_symbol expire strike;
run;
data upper1;
set upper;
by tdate stock_symbol expire strike;
if first.expire then output;
rename strike=astrike;
run;
on the following data set:
tdate stock_symbol expiration strike
9/11/2012 C 9/16/2012
2012 Oct 19
4
Creating a new by variable in a dataframe
Hello,
I have a dataframe w/ 3 variables of interest: transaction,date(tdate) &
time(event_tim).
How could I create a 4th variable (last_trans) that would flag the last
transaction of the day for each day?
In SAS I use:
proc sort data=all6;
by tdate event_tim;
run;
/*Create last transaction flag per day*/
data all6;
set all6;
by tdate event_tim;
last_trans=last.tdate;
Thanks
2011 Feb 28
1
Creating new variables. How do you get them into a data frame?
Hi
I'm an R newbie. I can't seem to add new variables to data frames. Here are
the stages
(1) I import the data using read.csv.
(2) I fix it using fix(data)
(3) I create a new variable using
spos<-tagPOS(stim,language="en",model=NULL,tagdict=NULL).
(tagPOS is a function in the OpenNLP toolkit, which tags a string for part
of speech. "stim" is a variable in the
2018 Apr 15
4
Adding a new conditional column to a list of dataframes
Hi all ..,
I have a list of 7000 dataframes with similar column headers and I wanted to add a new column to each dataframe based on a certain condition which is the same for all dataframes.
When I extract one dataframe and apply my code it works very well as follows :-
First suppose this is my first dataframe in the list
> OneDF <- Mylist[[1]]
> OneDF
ID Pdate
2018 Mar 29
1
Problem with my function using as.POSIXct
Hello all:
I wrote a function:
my.bastimeToSynoptic <- function(x) {
f<-unlist(strsplit(as.character(x), " "))
hr<-unlist(strsplit(f[2], ":"))
if(as.numeric(hr[1])<6) {
synoptic<-"00"
}
else {
synoptic<-as.integer(as.numeric(hr[1])/6)*6
}
tdate<-paste(c(f[1],"
2013 Jun 07
1
Function nlme::lme in Ubuntu (but not Win or OS X): "Non-positive definite approximate variance-covariance"
Dear all,
I am estimating a mixed-model in Ubuntu Raring (13.04¸ amd64), with the
code:
fm0 <- lme(rt ~ run + group * stim * cond,
random=list(
subj=pdSymm(~ 1 + run),
subj=pdSymm(~ 0 + stim)),
data=mydat1)
When I check the approximate variance-covariance matrix, I get:
> fm0$apVar
[1] "Non-positive definite
2015 Nov 06
2
(sin asunto)
Hola a tod en s,
sigo intentando representar una variable en función de meses. En la columna
Mesos tengo los meses de la siguiente manera:
01/08/1996, 01/09/1996 etc.
He probado con el siguiente comando:
plot(Mesos, Serie01)
obteniendo
y tendría que obtener:
[image: Imágenes integradas 2]
Pero donde pone Observation Index, me gustaria tener los meses (para esta
grafica he usado
2011 Mar 22
1
how to convert a data.frame to a list of dist objects for individual differences MDS?
I have a 45 x 16 data frame consisting of dissimilarities among 10
colors, giving in each
column the 45 = 10*9/2 pairwise judgments for one of 16 subjects. The
rownames
identify each pair of colors, e.g, "AC" = ("A","C"), and the pairs are
ordered by columns
in the lower triangle of each distance matrix.
> helm.raw <-
2018 Apr 15
0
Adding a new conditional column to a list of dataframes
> On Apr 15, 2018, at 4:08 AM, Allaisone 1 <Allaisone1 at hotmail.com> wrote:
>
>
> Hi all ..,
>
>
> I have a list of 7000 dataframes with similar column headers and I wanted to add a new column to each dataframe based on a certain condition which is the same for all dataframes.
>
>
> When I extract one dataframe and apply my code it works very well as
2013 Jul 20
1
how to calculate the average values of each row in a matrix
Hello,
I have a matrix (class matrix) composed of GridCell (row and column).
The matrix value is the beta diversity index value between two grids.
Now I would like to get the average value of each GridCell.
Please kindly advise how to make the calculation.
Thank you.
Elaine
The matrix looks like (cited from Michael Friendly)
I would like to get the average value of each color.
Obs
2009 Sep 29
2
rbind for a list
Dear All,
I´m using the following code:
all1<-gg2[[1]][[1]]; for(i in 1:48){ all1 <- rbind(all1,gg2[[i]][[1]]) }
to create a new matrix that contains all the matrices in a list called gg2.
gg2 is a list that looks like
>> gg2
[[1]]
[[1]][[1]]
<matrix one>
[[2]]
[[2]][[1]]
<matrix two>
.
.
.
[[48]]
[[48]][[1]]
<matrix 48>
Is there a faster way to do the rbind?
2010 Sep 17
7
removing specific rows from array
I'm attempting to create an array of treatment comparisons for modelling data generation. This involves comparison of one treatment (c2) with another (c3), relative to a common comparator (c1).
Attached code gives me the correct array but need to remove duplicates. Duplicates relate only to c2 and c3
such that I need to remove
r3 because c2 and c3 are same as r1 with c2 and c3 swapped
r5
2007 Nov 06
1
Problem with a non-factor, non-numeric variable in a data.frame
Dear R list,
I would like to perform an ANOVA in a set of measurements, but I have
problems formatting the data.
The data is a two dimensional array containing two columns:
- "Stim" : the type of stimulation (string)
- "Ratio" : a ratio of two numeric values
Now, because some values are missing in the data (defaulting to zero),
part of this array will be populated with NA
2000 Oct 26
1
competing risks survival analysis
I will have data in the following form:
Time resp type stim type
300 a A
200 b A
155 a B
250 b B
80 c A
1000 d B
...
c is left censored observation; d is right censored
This sort of problem is discussed in Chap 9 of Cox & Oakes Analysis of
Survival Data under the name
2013 Apr 03
5
Can package plyr also calculate the mode?
I am trying to replicate the SAS proc univariate in R. I got most of the
stats I needed for a by grouping in a data frame using:
all1 <- ddply(all,"ACT_NAME", summarise, mean=mean(COUNTS), sd=sd(COUNTS),
q25=quantile(COUNTS,.25),median=quantile(COUNTS,.50),
q75=quantile(COUNTS,.75),
q90=quantile(COUNTS,.90), q95=quantile(COUNTS,.95),
q99=quantile(COUNTS,.99) )