Dear all,
i would like to count the number of times where I have combined occurrences of
the categories of 2 variables.
For instance, in the dataframe below, i would like to know how many times each
author (au1, au2, au3 represent the first, second, third author) is associated
with each of t
Dear all,
I have a dataframe of names (netw), with each cell including last name and
initials of an author; some cells have NA. I would like to extract only the
last name from each cell; this new dataframe is calle 'res'
Here is what I do:
res <- data.frame(matrix(NA, nrow=dim(netw)[1], ncol=
OK thanks for the tips. I have abandonned the use of cbidn in dataframe. I've
used the obth dcast() and melt() and they both work fine. Thanks again
David Biau
>
> De : David Winsemius
>À : arun
>Cc : R help ; Biau David
>Envoyé le :
z ds', NA, 'chung p', ' biau dj', 'marmor
s', 'bhumbra r', 'pansuriya tc', NA)
netw <- data.frame(au1, au2, au3)
res <- data.frame(matrix(NA, nrow=dim(netw)[1], ncol=dim(netw)[2]))
for (i in 1:dim(netw)[2])
{
wh <- regexpr('[a-z]{3,}
works great thanks. And you cut off my code a lot and removed the loop.
David Biau
>
> De : Uwe Ligges
>À : Biau David
>Cc : arun ; r help list
>Envoyé le : Dimanche 13 janvier 2013 18h22
>Objet : Re: [R] extracting character values
>
thanks too. It works also perfect. Not sure I understand all the code though:
will have to look into it!
David Biau
>
> De : arun
>À : Biau David
>Cc : R help ; Uwe Ligges
>
>Envoyé le : Dimanche 13 janvier 2013 18h36
>Objet
Dear all,
I am working on an author network and to do so I have to arrange a data.frame
(tutu) crossing author names (rows) per publication number (column). The
participation of the author to a study is indicated by a 1 and 0 otherwise.
I have a vector (xaulist) of all the names of authors and
ing of the sort?
thanks,
David Biau
>
> De : arun
>À : Biau David
>Cc : R help
>Envoyé le : Mardi 15 janvier 2013 21h54
>Objet : Re: [R] removing loops from code in making data.frame
>
>Hi,
>
>You could also do this:
&
Dear All,
I have a data frame of vectors of publication names such as 'pub':
pub1 <- c('Brown DK, Santos R, Rome DF, Don Juan X')
pub2 <- c('Benigni D')
pub3 <- c('Arstra SD, Van den Hoops DD, lamarque D')
pub <- rbind(pub1, pub2, pub3)
I would like to construct a dataframe with only author's
thanks, it works well. I have to work on Arun's previous answer to make it work
too.
David
>
> De : Rui Barradas
>À : Biau David
>Cc : r help list
>Envoyé le : Mercredi 23 janvier 2013 19h57
>Objet : Re: [R] extracting characters
Hi,
I am trying to model a score over time. This score shows a ceiling effect. I
was
willing to use a longitudinal tobit model, such as the one described by Twisk
et
al. (Twisk_Longitudinal tobit regression: A new approach to analyze outcome
variables with floor or ceiling effects_JCE_2009) b
Dear R help list,
I am modeling some survival data with coxph and survreg (dist='weibull') using
package survival. I have 2 problems:
1) I do not understand how to interpret the regression coefficients in the
survreg output and it is not clear, for me, from ?survreg.objects how to.
Here is an
_
De : David Winsemius
Cc : r help list
Envoyé le : Sam 13 novembre 2010, 19h 55min 10s
Objet : Re: [R] interpretation of coefficients in survreg AND obtaining the
hazard function for an individual given a set of predictors
On Nov 13, 2010, at 12:51 PM, Biau David wrote:
> Dea
Dear Prof Lumley,
This is a very clear, precise, and useful answer to all my questions.
Thank you very much.
David Biau.
De : Thomas Lumley
Cc : r help list
Envoyé le : Dim 14 novembre 2010, 23h 54min 23s
Objet : Re: [R] interpretation of coefficients in
Dear Prof Therneau,
thank yo for this information: this is going to be most useful for what I want
to do. I will look into the ACF model.
Yours,
David Biau.
De : Terry Therneau
Cc : r-help@r-project.org
Envoyé le : Lun 15 novembre 2010, 15h 33min 23s
Obje
Hello,
I would like to get the likelihood ratio and score tests for specific variables
in a multivariate coxph model. The default is Wald, so the tests for each
separate variable is based on Wald's test. I have the other tests for the full
model but I don't know how to get them for each variabl
p=2.375e-05
David Biau.
De : David Winsemius
Cc : r help list
Envoyé le : Ven 30 juillet 2010, 17h 34min 28s
Objet : Re: [R] COXPH: how to get the score test and likelihood ratio test for
a
specific variable in a multivariate Coxph ?
On Jul 30, 2010, at 11:08 AM, Biau David wrote:
&g
rneau, Terry M., Ph.D."
À : David Winsemius ; Biau David
Cc : r help list
Envoyé le : Ven 30 juillet 2010, 19h 07min 15s
Objet : RE: Re : [R] COXPH: how to get the score test and likelihood ratio test
for a specific variable in a multivariate Coxph ?
The Wald, score, and LR tests are discussed
Hello,
I am modeling some survival data wih cph (Design). I have modeled a predictor
which showed non linear effect with restricted cubic splines. I would like to
retrieve the se(coef) for other, linear, predictors. This is just to make nice
LateX tables automatically. I have the coefficients w
4:03 PM, Biau David wrote:
> Hello,
>
> I am modeling some survival data wih cph (Design). I have modeled a predictor
> which showed non linear effect with restricted cubic splines. I would like to
> retrieve the se(coef) for other, linear, predictors.
The cph object has a
s is coded in print.cph.fit (library(rms))
On 08/05/2010 04:03 PM, Biau David wrote:
> Hello,
>
> I am modeling some survival data wih cph (Design). I have modeled a predictor
> which showed non linear effect with restricted cubic splines. I would like to
> retrieve the se(coef) for
Hello,
I would like, if it is possible, to compare the effect of a variable across
regression models. I have looked around but I haven't found anything. Maybe
someone could help? Here is the problem:
I am studying the effect of a variable (age) on an outcome (local recurrence:
lr). I have buil
Frank
Frank E Harrell Jr Professor and ChairmanSchool of Medicine
Department of Biostatistics Vanderbilt University
On Fri, 13 Aug 2010, Biau David wrote:
> Hello,
>
> I would like, if it is possible, to compare the effect of a variable across
> regressi
work for your goals, is to embed all models
> in a grand model that is used for inference.
>
> When coefficients ARE comparable in some sense, you can use the bootstrap to
>get
> confidence bands for differences in regressor effects between models.
>
> Frank
>
> Frank E Ha
Hello,
I have a dataframe (var_1, var_2, ..., var_n) and I would like to export
summary statistics to Latex in the form of a table. I want specific summary
statistics by crossing numerous variables 2x2 AT ONCE. In each cell I would
like sometimes to have the median (Q1 - Q3), or frequency and p
Hi,
>
>I am trying to describe a data.frame by obtaining multiple crosstable summary
>statistics at once. I have tried table, xtab, crosstable, summaryBy and
>describe but none of these functions seems to allow muliple conparisons at
>once.
> Here, is what I would like to do:
>
>I have, for in
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