Hi Thierry,
the values in the example data frame are fake numbers, my original data frame
has hundreds of row and values are in wide range, not min or max of two
variables, also the number 23 is also different in different data frames.
I agree I need to use vectorized ifelse, but I got confused when there are more
than two conditions inside of ifelse function. I will look into ifelse function
Thank you,
Ding
From: Thierry Onkelinx [thierry.onkel...@inbo.be]
Sent: Tuesday, April 7, 2020 11:48 AM
To: Yuan Chun Ding
Cc: r-help mailing list
Subject: Re: [R] to create a new variable based on values in other variables
Dear Ding,
It seems that you are looking for the ifelse() function. Clear use of pmax()
and pmin() reduces the number of if statements.
m1 <- c(12, 23, 22, 23)
m2 <- c(23, 23, 3, 5)
Ravg <- ifelse(
pmax(m1, m2) == 23,
pmin(m1, m2),
(m1 + m2) / 2
)
Best regards,
ir. Thierry Onkelinx
Statisticus / Statistician
Vlaamse Overheid / Government of Flanders
INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND
FOREST
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
thierry.onkel...@inbo.be
Havenlaan 88 bus 73, 1000 Brussel
www.inbo.be
///////////////////////////////////////////////////////////////////////////////////////////
To call in the statistician after the experiment is done may be no more than
asking him to perform a post-mortem examination: he may be able to say what the
experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not ensure
that a reasonable answer can be extracted from a given body of data. ~ John
Tukey
///////////////////////////////////////////////////////////////////////////////////////////
Op di 7 apr. 2020 om 20:35 schreef Yuan Chun Ding <ycd...@coh.org>:
Hi R users,
I want to create a new variable, Ravg, in data frame tem2 based on values of
two other variables m1 and m2.
the condition:
if m1 = 23 and m2 =23 then Ravg =23;
else if m1 != 23 and m2=23 then Ravg =m1;
else if m1 =23 and m2 !=23 then Ravg=m2;
else Ravg=average of m1 and m2;
the Ravg variable should be same as m3 variable in the following small
example.
my R code did not generate errors but not generate a new variable.
Ravg <- "rare_allele"
tem2 <-data.frame(m1=c(12, 23, 22, 23), m2=c(23, 23, 3, 5), m3 =c(12, 23,
12.5, 5))
for (r in 1:nrow(tem2)) {
if (tem2$m1[r] ==23 & tem2$m2[r] ==23) {
tem2[[Ravg]][r] ==23} else if(tem2$m1[r] ==23 & tem2$m2[r] !=23){
tem2[[Ravg]][r] ==tem2$m2[r]} else if (tem2$m1[r] !=23 & tem2$m2[r] ==23) {
tem2[[Ravg]][r] ==tem2$m1[r]} else {
tem2[[Ravg]][r] == mean(tem2$m1[r] + tem2$m2[r])}
}
Thank you,
Ding
----------------------------------------------------------------------
------------------------------------------------------------
-SECURITY/CONFIDENTIALITY WARNING-
This message and any attachments are intended solely for the individual or
entity to which they are addressed. This communication may contain information
that is privileged, confidential, or exempt from disclosure under applicable
law (e.g., personal health
information, research data, financial information). Because this e-mail has
been sent without encryption, individuals other than the intended recipient may
be able to view the information, forward it to others or tamper with the
information without the knowledge
or consent of the sender. If you are not the intended recipient, or the
employee or person responsible for delivering the message to the intended
recipient, any dissemination, distribution or copying of the communication is
strictly prohibited. If you received
the communication in error, please notify the sender immediately by replying
to this message and deleting the message and any accompanying files from your
system. If, due to the security risks, you do not wish to receive further
communications via e-mail,
please reply to this message and inform the sender that you do not wish to
receive further e-mail from the sender. (LCP301)
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
