Displaying 20 results from an estimated 10000 matches similar to: "extract data from lm object and then use again?"
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
2008 Sep 02
2
cluster a distance(analogue)-object using agnes(cluster)
I try to perform a clustering using an existing dissimilarity matrix that I
calculated using distance (analogue)
I tried two different things. One of them worked and one not and I don`t
understand why.
Here the code:
not working example
library(cluster)
library(analogue)
iris2<-as.data.frame(iris)
str(iris2)
'data.frame': 150 obs. of 5 variables:
$ Sepal.Length: num 5.1 4.9 4.7
2012 Aug 01
3
Neuralnet Error
I require some help in debugging this codeĀ
library(neuralnet)
ir<-read.table(file="iris_data.txt",header=TRUE,row.names=NULL)
ir1 <- data.frame(ir[1:100,2:6])
ir2 <- data.frame(ifelse(ir1$Species=="setosa",1,ifelse(ir1$Species=="versicolor",0,"")))
colnames(ir2)<-("Output")
ir3 <- data.frame(rbind(ir1[1:4],ir2))
2013 Jan 01
3
translate grouped data to their centroid
Given a data set with a group factor, I want to translate the numeric
variables to their
centroid, by subtracting out the group means (adding back the grand means).
The following gives what I want, but there must be an easier way using
sweep or
apply or some such.
iris2 <- iris[,c(1,2,5)]
means <- colMeans(iris2[,1:2])
pooled <- lm(cbind(Sepal.Length, Sepal.Width) ~ Species,
2006 Jul 11
2
R newbie: logical subsets
Hello! I'm a newcomer to R hoping to replace some convoluted database
code with an R script. Unfortunately, I haven't been able to figure out
how to implement the following logic.
Essentially, we have a database of transactions that are coded with a
geographic locale and a type. These are being loaded into a data.frame
with named variables city, type, and price. E.g., trans$city
2010 Sep 21
5
removed data is still there!
I'm confused, hope someone can point out what is not obvious to me.
I thought I was creating a new data frame by 'deleting' rows from an
existing dataframe - I've tried 2 methods.
But this new data frame seems to remember values from its parent - even
though there are no occurences.
Where does it get the values versicolor and virginica from and give then a
count of 0?
What
2012 Apr 15
2
xyplot type="l"
Probably a stupidly simple question, but I wouldn't know how to google it:
xyplot(neuro ~ time | UserID, data=data_sub)
creates a proper plot.
However, if I add
type = "l"
the lines do not go first through time1, then time2, then time3 etc but in
about 50% of all subjects the lines go through points seemingly random
(e.g. from 1 to 4 to 2 to 5 to 3).
The lines always start at time
2002 Mar 17
3
apply problem
> data(iris)
# iris3 is first 3 rows of iris
> iris3 <- iris[1:3,]
# z compares row 1 to each row of iris3 and is correctly
computed
> z <- c(F,F,F)
> for(i in seq(z)) z[i] <- identical(iris3[1,],iris3[i,])
> z
[1] TRUE FALSE FALSE
# this should do the same but is incorrect
> apply(iris3,1,function(x)identical(x,iris3[1,]))
1 2 3
FALSE FALSE FALSE
2009 Feb 12
2
barplot() x axes are not updated after removal of categories from the dataframe
Hi all,
I'd be grateful for your help. I am a new user struggling with a barplot
issue.
I am plotting categories (X axis) and their mean count (Y axies) with
barplot().
The first call to barplot works fine.
I remove records from the dataframe using final=[!final$varname == "some
value",]
I echo the dataframe and the records are no longer in the dataframe.
When I call plot again
2006 May 30
1
when dimensionality is larger than the number of observations?
Hi, there:
Can anyone here kindly point some good reference or links on this topic?
Esp. some solutions from BioConductor or R, when dealing with
microarray-like, "fat" data?
thanks,
--
Weiwei Shi, Ph.D
"Did you always know?"
"No, I did not. But I believed..."
---Matrix III
[[alternative HTML version deleted]]
2010 Jun 09
4
question about "mean"
Hi there:
I have a question about generating mean value of a data.frame. Take
iris data for example, if I have a data.frame looking like the following:
---------------------
Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1 5.1 3.5 1.4
0.2 setosa
2 4.9 3.0 1.4
0.2
2018 Mar 23
2
aggregate() naming -- bug or feature
In the examples below, the first loses the name attached by foo(), the second retains names attached by bar(). Is this an intentional difference? I?d prefer that the names be retained in both cases.
foo <- function(x) { c(mean = base::mean(x)) }
bar <- function(x) { c(mean = base::mean(x), sd = stats::sd(x))}
aggregate(iris$Sepal.Length, by = list(iris$Species), FUN = foo)
#>
2013 Jan 16
4
Get a percent variable based on group
Dear all, I'd like to get a percentage variable based on a group, but without creating a new data frame.
For example:
data(iris)
iris$percent <-unlist(tapply(iris$Sepal.Length,iris$Species,function(x) x/sum(x, na.rm=TRUE)))
This does not work, I should have only three standard values, respectively for setosa, versicolor, and virginica. How can I do this?
MANY THANKS,
Karine
2012 Jun 11
1
saving sublist lda object with save.image()
Greetings R experts,
I'm having some difficulty recovering lda objects that I've saved within sublists using the save.image() function. I am running a script that exports a variety of different information as a list, included within that list is an lda object. I then take that list and create a list of that with all the different replications I've run. Unfortunately I've been
2011 Aug 16
3
Newbie question - struggling with boxplots
Hopefully I will not be flamed for this on the list, but I am starting out
with R and having some trouble with combining plots.
I am playing with the famous iris dataset (checking out example dataset in R
while reading through Introduction to datamining)
What I would like to do is create three graphs (combined boxplots) besides
each other for each of the three species (Setosa, Versicolour and
2005 Sep 16
6
How do I get the row indices?
Hi,
I was wondering if it's possible to get the row
numbers from a filtering. Here's an example:
# give me the rows with sepal.length == 6.2
iris[(iris[,1]==6.2),]
# output
Sepal.Length Sepal.Width Petal.Length Petal.Width
Species
69 6.2 2.2 4.5 1.5
versicolor
98 6.2 2.9 4.3 1.3
versicolor
127 6.2
2018 Jan 28
2
Newbie wants to compare 2 huge RDSs row by row.
The anti_join from the package dplyr might also be handy.
install.package("dplyr")
library(dplyr)
anti_join (x1, x2)
You can get help on the different functions by ?function.name(), so
?anti_join() will bring you help - and examples - on the anti_join
function.
It might be worth testing your approach on a small subset of the data. That
makes it easier for you to follow what happens
2005 Apr 07
2
axis colors in pairs plot
The following command produces red axis line in a pairs
plot:
pairs(iris[1:4], main = "Anderson's Iris Data -- 3 species",
pch = "+", col = c("red", "green3", "blue")[unclass(iris$Species)])
Trying to fool pairs in the following way produces the
same plot as above:
pairs(iris[1:4], main = "Anderson's Iris Data -- 3
2004 Aug 21
2
more on apply on data frame
Hi R People:
Several of you pointed out that using "tapply" on a data frame will work on
the iris data frame.
I'm still having a problem.
The iris data frame has 150 rows, 5 variables. The first 4 are numeric,
while the last is a factor, which has the Species names.
I can use tapply for 1 variable at a time:
>tapply(iris[,1],iris[,5],mean)
setosa versicolor virginica
2008 Aug 07
6
multiple tapply
Hi folk,
I tried this and it works just perfectly
tapply(iris[,1],iris[5],mean)
but, how to obtain a single table from multiple variables?
In tapply x is an atomic object so this code doesn't work
tapply(iris[,1:4],iris[5],mean)
Thanx and great summer holidays
Gianandrea
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