Dear all,
I am writing as I would like your help. I have a dataframe with two columns, ASB
and Flow, where the the first one has values 1, 2 or 3 and the second flow data.
Something like that:
ASBclass??? Flow1????????????? 11.51?????????????? 9.2
2????????????? 10.5
3?????????????? 6.7??...????????????? ...
I would like to produce a third column named eg. deviation where it would get me
values based on if ASBclass is 1, multiply Flow by 0.1; if ASBclass is 2 then
multiply Flow by 0.15 and if ASBclass is 3 then multiply by 0.2.
If (ASBclass=1) { deviation<-Flow*0.1}
If (ASBclass=2) { deviation<-Flow*0.15}If (ASBclass=1) {
deviation<-Flow*0.2}
I am not sure whether I should add the else function and how can I combine these
separate functions.
Can anyone help me on that?
Thank you very much.
Kind regardsMaria
[[alternative HTML version deleted]]
Maria: Have you read An Intro to R or other R tutorial? There are many on the web and this is a basic idea that they would explain (with examples). ?ifelse ##a vectorized kind of if conditional is one way to do this (though it can get a little convoluted). There are others (e.g. splitting and recombining -- see the plyr package), which others may suggest. Nevertheless, time spent with a tutorial would be useful. Cheers, Bert Bert Gunter "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." -- Clifford Stoll On Tue, Sep 15, 2015 at 3:56 AM, Maria Lathouri <mlathouri at yahoo.gr> wrote:> Dear all, > > I am writing as I would like your help. I have a dataframe with two columns, ASB and Flow, where the the first one has values 1, 2 or 3 and the second flow data. Something like that: > ASBclass Flow1 11.51 9.2 > 2 10.5 > 3 6.7 ... ... > I would like to produce a third column named eg. deviation where it would get me values based on if ASBclass is 1, multiply Flow by 0.1; if ASBclass is 2 then multiply Flow by 0.15 and if ASBclass is 3 then multiply by 0.2. > > If (ASBclass=1) { deviation<-Flow*0.1} > If (ASBclass=2) { deviation<-Flow*0.15}If (ASBclass=1) { deviation<-Flow*0.2} > I am not sure whether I should add the else function and how can I combine these separate functions. > > Can anyone help me on that? > Thank you very much. > > Kind regardsMaria > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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.
Tena koe Maria
It seems you need to multiply Flow by 0.05+ASBClass/20 (i.e., no if calls are
necessary)
HTH ....
Peter Alspach
-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Maria
Lathouri
Sent: Tuesday, 15 September 2015 10:57 p.m.
To: r-help at r-project.org
Subject: [R] Multiple if function
Dear all,
I am writing as I would like your help. I have a dataframe with two columns, ASB
and Flow, where the the first one has values 1, 2 or 3 and the second flow data.
Something like that:
ASBclass??? Flow1????????????? 11.51?????????????? 9.2
2????????????? 10.5
3?????????????? 6.7??...????????????? ...
I would like to produce a third column named eg. deviation where it would get me
values based on if ASBclass is 1, multiply Flow by 0.1; if ASBclass is 2 then
multiply Flow by 0.15 and if ASBclass is 3 then multiply by 0.2.
If (ASBclass=1) { deviation<-Flow*0.1}
If (ASBclass=2) { deviation<-Flow*0.15}If (ASBclass=1) {
deviation<-Flow*0.2} I am not sure whether I should add the else function and
how can I combine these separate functions.
Can anyone help me on that?
Thank you very much.
Kind regardsMaria
[[alternative HTML version deleted]]
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... but this only works if ASBclass is numeric. What if it is a factor (or even character)? One can always finesse factors in simple cases like this, but for 2 reasons, I don't think it's a good idea. 1. One should make use of a factor's API, rather than its internal integer representation(which, I grant, ain't likely to change); 2. For more complicated alternatives (e.g. entirely different functions depending on the factor value) it won't work anyway. For simple cases, ifelse() seems reasonable; but for more alternatives -- say 10 or 50 -- this becomes too cumbersome (imho). I think the split and recombine approach then becomes the best option, but maybe there is some easier, shorter, approach that I am overlooking. Please correct me if this is the case. Best, Bert Bert Gunter "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." -- Clifford Stoll On Tue, Sep 15, 2015 at 12:23 PM, Peter Alspach <Peter.Alspach at plantandfood.co.nz> wrote:> Tena koe Maria > > It seems you need to multiply Flow by 0.05+ASBClass/20 (i.e., no if calls are necessary) > > HTH .... > > Peter Alspach > > -----Original Message----- > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Maria Lathouri > Sent: Tuesday, 15 September 2015 10:57 p.m. > To: r-help at r-project.org > Subject: [R] Multiple if function > > Dear all, > > I am writing as I would like your help. I have a dataframe with two columns, ASB and Flow, where the the first one has values 1, 2 or 3 and the second flow data. Something like that: > ASBclass Flow1 11.51 9.2 > 2 10.5 > 3 6.7 ... ... > I would like to produce a third column named eg. deviation where it would get me values based on if ASBclass is 1, multiply Flow by 0.1; if ASBclass is 2 then multiply Flow by 0.15 and if ASBclass is 3 then multiply by 0.2. > > If (ASBclass=1) { deviation<-Flow*0.1} > If (ASBclass=2) { deviation<-Flow*0.15}If (ASBclass=1) { deviation<-Flow*0.2} I am not sure whether I should add the else function and how can I combine these separate functions. > > Can anyone help me on that? > Thank you very much. > > Kind regardsMaria > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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. > > The contents of this e-mail are confidential and may be subject to legal privilege. > If you are not the intended recipient you must not use, disseminate, distribute or > reproduce all or any part of this e-mail or attachments. If you have received this > e-mail in error, please notify the sender and delete all material pertaining to this > e-mail. Any opinion or views expressed in this e-mail are those of the individual > sender and may not represent those of The New Zealand Institute for Plant and > Food Research Limited. > ______________________________________________ > R-help at 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.
Hi Maria, Why not exploit some simple boolean facts (FALSE=0, TRUE=1) in your calculation, so ASBclass = c(1,2,2,3,2,1) Flow = c(1,1,1,1,1,1) factor = ((ASBclass==1) * 0.1 + (ASBclass==2) * 0.15 + (ASBclass==3) * 0.2) deviation = factor * Flow cheers Peter> On 15 Sep 2015, at 12:56, Maria Lathouri <mlathouri at yahoo.gr> wrote: > > Dear all, > > I am writing as I would like your help. I have a dataframe with two columns, ASB and Flow, where the the first one has values 1, 2 or 3 and the second flow data. Something like that: > ASBclass Flow1 11.51 9.2 > 2 10.5 > 3 6.7 ... ... > I would like to produce a third column named eg. deviation where it would get me values based on if ASBclass is 1, multiply Flow by 0.1; if ASBclass is 2 then multiply Flow by 0.15 and if ASBclass is 3 then multiply by 0.2. > > If (ASBclass=1) { deviation<-Flow*0.1} > If (ASBclass=2) { deviation<-Flow*0.15}If (ASBclass=1) { deviation<-Flow*0.2} > I am not sure whether I should add the else function and how can I combine these separate functions. > > Can anyone help me on that? > Thank you very much. > > Kind regardsMaria > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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.