Displaying 20 results from an estimated 1000 matches similar to: "From xtabs to matrix"
2010 Jun 14
3
remove last char of a text string
Dear R experts,
is there a simple way to remove the last char of a text string?
substr() function use as parameter start end only... but my strings are of
different length...
01asap05a -> 01asap05
02ee04b -> 02ee04
Thank you all,
Gianandrea
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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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2008 Aug 28
3
drop unused levels in sqldf
Hi,
sqldf is a fantastic package, but when the SELECT procedure runs unused
levels remain in the output. I tried with the drop function, but without
success. Do you have any suggestions?
Thanx, Gianandrea
data(iris)
require(sqldf)
base<-sqldf("select * from iris where Species <> 'setosa'")
str(base) # Species with 3 levels!
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2009 Feb 19
2
dotplot points color
Dear list,
is it possible to change the background color of dotplot's points? I tried
in many ways but unsuccessfully
Thanks in advance
Gianandrea
require(lattice)
dotplot(variety ~ yield | site, data = barley, groups = year, pch=21)
dotplot(variety ~ yield | site, data = barley, groups = year, pch=21,
bg=c("2","3")) ??!!!
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2018 Jan 09
0
SpreadLevelPlot for more than one factor
Dear Sir,
Many thanks for your reply.
I have a query.
I have a whole set of distributions which should be made normal /
homoscedastic. Take for instance the warpbreaks data set.
We have the following boxplots for the warpbreaks dataset:
a. boxplot(breaks ~ wool)
b. boxplot(breaks ~ tension)
c. boxplot(breaks ~ interaction(wool,tension))
d. boxplot(breaks ~ wool @ each level of tension)
e.
2018 Jan 14
1
SpreadLevelPlot for more than one factor
Dear Ashim,
I?ll address your questions briefly but they?re really not appropriate for
this list, which is for questions about using R, not general statistical
questions.
(1) The relevant distribution is within cells of the wool x tension
cross-classification because it?s the deviations from the cell means that
are supposed to be normally distributed with equal variance. In the
warpbreaks data
2018 Jan 07
2
SpreadLevelPlot for more than one factor
Dear All,
I want a transformation which will make the spread of the response at all
combinations
of 2 factors the same.
See for example :
boxplot(breaks ~ tension * wool, warpbreaks)
The closest I can do is :
spreadLevelPlot(breaks ~tension , warpbreaks)
spreadLevelPlot(breaks ~ wool , warpbreaks)
I want to do :
spreadLevelPlot(breaks ~tension * wool, warpbreaks)
But I get :
>
2018 Jan 07
2
SpreadLevelPlot for more than one factor
Dear Ashim,
Try spreadLevelPlot(breaks ~ interaction(tension, wool), data=warpbreaks) .
I hope this helps,
John
-----------------------------
John Fox, Professor Emeritus
McMaster University
Hamilton, Ontario, Canada
Web: socialsciences.mcmaster.ca/jfox/
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Ashim
> Kapoor
> Sent:
2012 Jul 27
1
Understanding the intercept value in a multiple linear regression with categorical values
Hi!
I'm failing to understand the value of the intercept value in a
multiple linear regression with categorical values. Taking the
"warpbreaks" data set as an example, when I do:
> lm(breaks ~ wool, data=warpbreaks)
Call:
lm(formula = breaks ~ wool, data = warpbreaks)
Coefficients:
(Intercept) woolB
31.037 -5.778
I'm able to understand that the value of
2018 Jan 07
0
SpreadLevelPlot for more than one factor
Dear All,
we need to do :
library(car) for the spreadLevelPlot function
I forgot to say that.
Apologies,
Ashim
On Sun, Jan 7, 2018 at 10:37 AM, Ashim Kapoor <ashimkapoor at gmail.com> wrote:
> Dear All,
>
> I want a transformation which will make the spread of the response at all
> combinations
> of 2 factors the same.
>
> See for example :
>
>
2009 Mar 03
1
Self-Organizing Map analysis
Dear list,
I read the SOM package manual but I don't understand how to perform (for
example) 1) the SOM analysis on Iris data 2) with a visualization similar to
that of figure 7 in
http://www.cis.hut.fi/projects/somtoolbox/package/papers/techrep.pdf
Any suggestion? Thanks in advance,
Gianandrea
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2007 Aug 14
4
Problem with "by": does not work with ttest (but with lme)
Hello,
I would like to do a large number of e.g. 1000 paired ttest using the by-function. But instead of using only the data within the 1000 groups, R caclulates 1000 times the ttest for the full data set(The same happens with Wilcoxon test). However, the by-function works fine with the lme function.
Did I just miss something or is it really not working? If not, is there any other possibility to
2010 May 18
2
how to select rows per subset in a data frame that are max. w.r.t. a column
Hi,
I'd like to select one row in a data frame per subset which is maximal for a
particular value. I'm pretty close to the solution in the sense that I can
easily select the maximal values per subset using "aggregate", but I can't
really figure out how to select the rows in the original data frame that are
associated with these maximal values.
library(stats)
# this
2012 Nov 29
2
Deleting certain observations (and their imprint?)
I'm manipulating a large dataset and need to eliminate some observations based on specific identifiers. This isn't a problem in and of itself (using which.. or subset..) but an imprint of the deleted observations seem to remain, even though they have 0 observations. This is causing me problems later on. I'll use the dataset warpbreaks to illustrate, I apologize if this isn't in
2007 Sep 06
3
Warning message with aggregate function
Dear all,
When I use aggregate function as:
attach(warpbreaks)
aggregate(warpbreaks[, 1], list(wool = wool, tension = tension), sum)
The results are right but I get a warning message:
"number of items to replace is not a multiple of replacement length."
BTW: I use R version 2.4.1 in Ubuntu 7.04.
Your kind solutions will be great appreciated.
Best wishes
Yours, sincerely,
Xingwang
2020 May 02
1
issues with environment handling in model.frame()
Dear all,
model.frame behaves in a way I don't expect when both its formula and
subset argument are passed through a function call.
This works as expected:
model.frame(~wool, warpbreaks, breaks < 15)
#> wool
#> 14 A
#> 23 A
#> 29 B
#> 50 B
fun1 <- function(y) model.frame(~wool, warpbreaks, y)
fun1(with(warpbreaks, breaks < 15))
#> wool
#> 14
2013 Feb 25
1
quesion about SS of ANOVA
Hi all:
I have a quesion about ANOVA: Is SS(Sum of Square) of a specific factor constant with the number of factors changing?
dat1 includes one factor g1,and g1's SS is called SS_g1_dat1.
dat2 includes two factors g1,g2,and g1's SS is called SS_g1_dat2.
My quesion is: Is SS_g1_dat1 equals to SS_g1_dat2?
I have both "yes" and "no" reasons for the quesion,but
2006 Apr 25
1
by() and CrossTable()
I am attempting to produce crosstabulations between two variables for
subgroups defined by a third factor variable. I'm using by() and
CrossTable() in package gmodels. I get the printing of the tables first
and then a printing of each level of the INDICES. For example:
library(gmodels)
by(warpbreaks, warpbreaks$tension, function(x){CrossTable(x$wool,
x$breaks > 30,
2013 Apr 10
2
Table with n(%) formatting: A better way to do this?
Hello All,
Am learning to create tables with n(%) formatting using R. Below is a working example. I think this is not bad but wondered if there are better ways of doing it. Although it can be quite humbling, seeing good code helps me assess my progress as an R programmer.
Ultimately want to have code that I can turn into a function. Will then use the output produced to make tables using
2001 Sep 05
3
Bug in ftable?? (Was: Two-way tables of data, etc)
Further to the discussion between Murray Jorgensen and Brian Ripley,
it seems to me better to choose tabulations that will not come and bite
you. Suppose your data are sligtly irregular, e.g. (for the sake of
the argument):
data( warpbreaks )
warpbreaks$variant <- rep( 1:5, len=54 )
attach( warpbreaks )
tb <- table( wool, tension, variant )
tb
# in this case you would like to see:
tp