facing problem in setting order of the levels in factor

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facing problem in setting order of the levels in factor

Anant Saini
Hi all,

I'm just a beginner in R. I have a pretty basic doubt. This is the actual
quote I wrote
> x<-factor(c("M","F","M","T","M","T"))
> levels(x)=c("M","F","T")
> x
[1] F M F T F T
Levels: M F T
> table(x)
x
M F T
1 3 2

Expectation: I just wanted to change my baselevel from F to M. with the
number of M and F remaining constant

What exactly happened: The values of F and M also get exchanged along with
the change of base level from F to M


​Best,​

--

*Anant Saini*
------------------------------
*Indian Institute of Technology Bombay*
*Mob: +91 - 9967687330 *
*LinkedIn* : *in.linkedin.com/in/anantsaini*
<http://in.linkedin.com/in/anantsaini>

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Re: facing problem in setting order of the levels in factor

Ivan Calandra-4
Hi,

I think you are looking for this:

y <- factor(x, levels=c("M","F","T"))

If you use the function levels(), you change the labels, but not the
order, so that the first level (previously "F") will now be labeled "M",
the second (previously "M") will now be labeled "F" ,and so on.
This explains why in the table(x) at the end you get the same
frequencies in the same order, but the frequencies are associated with
different labels/levels.

To change the order of the levels (but without changing the actual
data), you need to change the level argument of the factor() function.

I hope this makes it clear, although I can imagine that my explanation
is not crystal clear...

Ivan

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Le 19/08/2016 à 12:13, Anant Saini a écrit :

> Hi all,
>
> I'm just a beginner in R. I have a pretty basic doubt. This is the actual
> quote I wrote
>> x<-factor(c("M","F","M","T","M","T"))
>> levels(x)=c("M","F","T")
>> x
> [1] F M F T F T
> Levels: M F T
>> table(x)
> x
> M F T
> 1 3 2
>
> Expectation: I just wanted to change my baselevel from F to M. with the
> number of M and F remaining constant
>
> What exactly happened: The values of F and M also get exchanged along with
> the change of base level from F to M
>
>
> ​Best,​
>

______________________________________________
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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.