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count appearence of zero in a vector

9 messages · Hermann Norpois, Sarah Goslee, arun +2 more

Original
Sarah Goslee
# 
sum(test == 0)
On Thu, Jan 3, 2013 at 5:49 PM, Hermann Norpois <hnorpois at googlemail.com> wrote:
---
Sarah Goslee
http://www.functionaldiversity.org
arun
# 
Hi,
YOu could use ?count() from library(plyr) or ?table() or ?sum()

count(test)[,2][count(test)[,1]==0]
#[1] 6
table(test)["0"]
#0 
#6 
A.K.




----- Original Message -----
From: Hermann Norpois <hnorpois at googlemail.com>
To: r-help at r-project.org
Cc: 
Sent: Thursday, January 3, 2013 5:49 PM
Subject: [R] count appearence of zero in a vector

Hello,

I wish to count how often zero (0) appears in the vector test.

test
[1] 1 1 1 1 1 1 2 1 1 1 0 2 0 1 1 0 0 0 1 1 1 0 1 2 1 1 1 1 1 1


I think of something like ...
... but actually I dont know how to carry on.

Could anybody give me a hint?

Thanks Hermann

??? [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Suzen, Mehmet
# 
Hi Hermann,

You may want to use ?which, to store the index as well (might be handy
in debugging or some other
purposes if zeros has some special meaning) :

test <- c(1, 1, 1 , 1 , 1, 1, 2, 1, 1, 1, 0, 2, 0, 1, 1, 0, 0, 0, 1,
1, 1, 0, 1, 2, 1, 1, 1, 1, 1, 1)
length(which(test==0))

But be careful when using == 0. If you are sure that elements are all
integers I prefer this

length(which(test <1)).

Or a safe tolerance value from .Machine, if you are dealing with double numbers.

length(which(test < .Machine$double.xmin))


-m
arun
# 
As long as there are no negative numbers, method2 and 3 works:
?test[1]<- -1
length(which(test==0))
#[1] 6
?length(which(test<1))
#[1] 7
?length(which(test < .Machine$double.xmin))
#[1] 7

length(which(abs(test)<1))
#[1] 6
?length(which(abs(test) < .Machine$double.xmin))
#[1] 6
A.K.




----- Original Message -----
From: "Suzen, Mehmet" <msuzen at gmail.com>
To: Hermann Norpois <hnorpois at googlemail.com>
Cc: R help <r-help at r-project.org>
Sent: Friday, January 4, 2013 12:27 AM
Subject: Re: [R] count appearence of zero in a vector

Hi Hermann,

You may want to use ?which, to store the index as well (might be handy
in debugging or some other
purposes if zeros has some special meaning) :

test <- c(1, 1, 1 , 1 , 1, 1, 2, 1, 1, 1, 0, 2, 0, 1, 1, 0, 0, 0, 1,
1, 1, 0, 1, 2, 1, 1, 1, 1, 1, 1)
length(which(test==0))

But be careful when using == 0. If you are sure that elements are all
integers I prefer this

length(which(test <1)).

Or a safe tolerance value from .Machine, if you are dealing with double numbers.

length(which(test < .Machine$double.xmin))


-m

______________________________________________
R-help at r-project.org mailing list
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.
Suzen, Mehmet
# 
I am always reserved about types and not sure how R auto casting works
internally.
In a large code using many different packages, I think being reserved about
this would not hurt.

Also, are there anyway to force R to be "strongly typed" similar to
Occaml etc...

mem
On 4 January 2013 16:35, arun <smartpink111 at yahoo.com> wrote:
Suzen, Mehmet
#
On 4 January 2013 17:47, Bert Gunter <gunter.berton at gene.com> wrote:
Thank you Bert for point out S4. Here is one trivial example:
Error in checkSlotAssignment(object, name, value) :
  assignment of an object of class ?numeric? is not valid for slot ?x?
in an object of class ?integerVector?; is(value, "integer") is not
TRUE
So this is pretty safe:
[1] 2