Displaying 14 results from an estimated 14 matches for "bfeeni".
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bfeeny
2012 Nov 21
6
Scaling values 0-255 -> -1 , 1 - how can this be done?
I have a dataframe in which I have values 0-255, I wish to transpose them such that:
if value > 127.5 value = 1
if value < 127.5 value = -1
I did something similar using the "binarize" function of the biclust package, this transforms my dataframe to 0 and 1 values, but I wish
to use -1 and 1 and looking for a way in R to do this.
Brian
2012 Dec 06
4
Assignment of values with different indexes
I would like to take the values of observations and map them to a new index. I am not sure how to accomplish this. The result would look like so:
x[1,2,3,4,5,6,7,8,9,10]
becomes
y[2,4,6,8,10,12,14,16,18,20]
The "newindex" would not necessarily be this sequence, but a sequence I have stored in a vector, so it could be all kinds of values. here is what happens:
> x <- rnorm(10)
2012 Nov 23
1
caret train and trainControl
I am used to packages like e1071 where you have a tune step and then pass your tunings to train.
It seems with caret, tuning and training are both handled by train.
I am using train and trainControl to find my hyper parameters like so:
MyTrainControl=trainControl(
method = "cv",
number=5,
returnResamp = "all",
classProbs = TRUE
)
rbfSVM <- train(label~., data =
2012 Mar 02
1
e1071 SVM: Cross-validation error confusion matrix
Hi,
I ran two svm models in R e1071 package: the first without cross-validation
and the second with 10-fold cross-validation.
I used the following syntax:
#Model 1: Without cross-validation:
> svm.model <- svm(Response ~ ., data=data.df, type="C-classification",
> kernel="linear", cost=1)
> predict <- fitted(svm.model)
> cm <- table(predict,
2012 Nov 18
1
Best prediction to use to use for basic problem?
I have a rather basic set of data. It is simply a variable that can be 0, 1 or 2 and its value over a series of time t0 - t9 like so:
y: 1 1 2 0 1 2 2 1 2 1
x: t0 t1 t2 t3 t4 t5 t6 t7 t8 t9
I need to predict what the value of y will be at t10 through t13.
As you can see its rather basic. I am rather new to solving these types of problems so I am looking for some
good straight forward things
2012 Dec 02
2
How to re-combine values based on an index?
I am able to split my df into two like so:
dataset <- trainset
index <- 1:nrow(dataset)
testindex <- sample(index, trunc(length(index)*30/100))
trainset <- dataset[-testindex,]
testset <- dataset[testindex,-1]
So I have the index information, how could I re-combine the data using that back into a single df?
I tried what I thought might work, but failed with:
2012 Nov 29
1
Help with this error "kernlab class probability calculations failed; returning NAs"
I have never been able to get class probabilities to work and I am relatively new to using these tools, and I am looking for some insight as to what may be wrong.
I am using caret with kernlab/ksvm. I will simplify my problem to a basic data set which produces the same problem. I have read the caret vignettes as well as documentation for ?train. I appreciate any direction you can give. I
2012 Nov 24
2
Building factors across two columns, is this possible?
I am trying to make it so two columns with similar data use the same internal numbers for same factors, here is the example:
> read.csv("test.csv",header =FALSE,sep=",")
V1 V2 V3
1 sun moon stars
2 stars moon sun
3 cat dog catdog
4 dog moon sun
5 bird plane superman
6 1000 dog 2000
> data <-
2012 Nov 19
6
How to subset my data and at the same time keep the balance?
Hi guys,
I have 1000 rows of a dataset. In my analysis, I need 70% of the data,
run my analysis and then use the remaining 30% to test my model.
Could anybody kindly help me on this?
Cheers
2012 Nov 20
1
Removing columns that are na or constant
I have a dataset that has many columns which are NA or constant, and so I remove them like so:
same <- sapply(dataset, function(.col){
all(is.na(.col)) || all(.col[1L] == .col)
})
dataset <- dataset[!same]
This works GREAT (thanks to the r-users list archive I found this)
however, then when I do my data sampling like so:
testSize <- floor(nrow(x) * 10/100)
test <-
2012 Nov 17
1
Strange problem with reading a pipe delimited file
I am trying to read in a pipe delimited file that has rows with varying number of columns, here is my sample data:
A|B|C|D
A|B|C|D|E|F
A|B|C|D|E
A|B|C|D|E|F|G|H|I
A|B|C|D
A|B|C|D|E|F|G|H|I|J
You can see line 6 has 10 columns. Yet, I can't explain why R does like so:
> test <- read.delim("mypaths4.txt", sep="|", quote=NULL, header=F,
2012 Nov 17
2
Using cbind to combine data frames and preserve header/names
I have a dataframe that has a header like so:
class value1 value2 value3
class is a factor
the actual values in the columns value1, value2 and value3 are 0-255, I wish to binarize these using biclust.
I can do this like so:
binarize(dataframe[,-1])
this will return a dataframe, but then I lose my first column class, so I thought I could combine it like so:
dataframe <-
2012 Dec 10
3
splitting dataset based on variable and re-combining
I have a dataset and I wish to use two different models to predict. Both models are SVM. The reason for two different models is based
on the sex of the observation. I wish to be able to make predictions and have the results be in the same order as my original dataset. To
illustrate I will use iris:
# Take Iris and create a dataframe of just two Species, setosa and versicolor, shuffle them
2012 Nov 20
3
data after write() is off by 1 ?
I am new to R, so I am sure I am making a simple mistake. I am including complete information in hopes
someone can help me.
Basically my data in R looks good, I write it to a file, and every value is off by 1.
Here is my flow:
> str(prediction)
Factor w/ 10 levels "0","1","2","3",..: 3 1 10 10 4 8 1 4 1 4 ...
- attr(*, "names")= chr