Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-30 Thread Jim Lemon

On 08/30/2011 12:06 AM, Bert Gunter wrote:

Jim et. al:

This is the second time I've seen this advice recently. Use logical
indexing: which(), though not wrong, is superfluous:


x[ !x %in% c(0,255)]  will do, rather than:

By golly, you're right, and it works even if x is a logical vector. I 
should have checked the operator precedence.


Jim

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-30 Thread jim holtman
But that is a good reason to always use parentheses:

x[ !(x %in% c(0,255))]

since some of the 'precendences' vary between languages.

On Tue, Aug 30, 2011 at 4:47 AM, Jim Lemon j...@bitwrit.com.au wrote:
 On 08/30/2011 12:06 AM, Bert Gunter wrote:

 Jim et. al:

 This is the second time I've seen this advice recently. Use logical
 indexing: which(), though not wrong, is superfluous:


 x[ !x %in% c(0,255)]  will do, rather than:

 By golly, you're right, and it works even if x is a logical vector. I should
 have checked the operator precedence.

 Jim

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-29 Thread Jim Lemon

chuan_zl wrote:

 Dear All.

 I am Chuan. I am beginner for R.I facing some problem in remove 
element from

 vector.I have a vector with size 238 element as follow(a part)

 [1] 0 18 24 33 44..[238] 255

 Let the vector label as x,I want remove element 0 and 255.I try use
 such function:

 x[x0  x255]

Hi Chuan,
If you want to remove the specific values 0 and 255 from your vector, try:

x-x[-which(x %in% c(0,255))]

Jim

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-29 Thread Bert Gunter
Jim et. al:

This is the second time I've seen this advice recently. Use logical
indexing: which(), though not wrong, is superfluous:


x[ !x %in% c(0,255)]  will do, rather than:

 If you want to remove the specific values 0 and 255 from your vector, try:

 x-x[-which(x %in% c(0,255))]

 Jim


-- Bert
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 https://stat.ethz.ch/mailman/listinfo/r-help
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-- 
Men by nature long to get on to the ultimate truths, and will often
be impatient with elementary studies or fight shy of them. If it were
possible to reach the ultimate truths without the elementary studies
usually prefixed to them, these would not be preparatory studies but
superfluous diversions.

-- Maimonides (1135-1204)

Bert Gunter
Genentech Nonclinical Biostatistics

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-29 Thread chuan_zl
Thank you friend for suggestion.

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-29 Thread chuan_zl
Thank you very much,friend.

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-29 Thread chuan_zl
Thank you very much,friend.

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-29 Thread chuan_zl
Thank you very much,friend.

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-29 Thread William Dunlap
 -Original Message-
 From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On 
 Behalf Of Bert Gunter
 Sent: Monday, August 29, 2011 7:07 AM
 To: Jim Lemon
 Cc: r-help@r-project.org
 Subject: Re: [R] Asking Favor For Remove element with Particular Value In 
 Vector
 
 Jim et. al:
 
 This is the second time I've seen this advice recently. Use logical
 indexing: which(), though not wrong, is superfluous:

which() will give the wrong answer if x does not
contain any elements of the set which you want to omit.
E.g.,
   x - 1:3
   x[-which(x %in% c(0,255))] # bad
  integer(0)
   x[!is.element(x, c(0,255))] # good
  [1] 1 2 3

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com 

 
 
 x[ !x %in% c(0,255)]  will do, rather than:
 
  If you want to remove the specific values 0 and 255 from your vector, try:
 
  x-x[-which(x %in% c(0,255))]
 
  Jim
 
 
 -- Bert
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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.
 
 
 
 
 --
 Men by nature long to get on to the ultimate truths, and will often
 be impatient with elementary studies or fight shy of them. If it were
 possible to reach the ultimate truths without the elementary studies
 usually prefixed to them, these would not be preparatory studies but
 superfluous diversions.
 
 -- Maimonides (1135-1204)
 
 Bert Gunter
 Genentech Nonclinical Biostatistics
 
 __
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 https://stat.ethz.ch/mailman/listinfo/r-help
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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-28 Thread eyildiz
You can use 'which' and negative subscripts to remove elements from a vector. 

 y-x[-(which(x==0|x==255))] 



chuan_zl wrote:
 
 Dear All.
 
 I am Chuan. I am beginner for R.I facing some problem in remove element
 from vector.I have a vector with size 238 element as follow(a part)
 
 [1] 0 18 24 33 44..[238] 255
 
 Let the vector label as x,I want remove element 0 and 255.I try use
 such function:
 
 x[x0  x255]
 
 However, I am fail since same results are give even try it for many
 times.I also try with shorter vector with 10 element. It is successfully
 resulted. So,want can I do for it. Kindly asking favor for expert here.
 Thank you very much.
 
 Chuan
 


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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-28 Thread jim holtman
Be careful about negating the 'which' in case there are no matches:

 x - 1:10
 x[-which(x == 11)]
integer(0)


Notice it deletes the whole vector.

Safer to use logical vectors:

 x[!(x==3 | x == 7)]
[1]  1  2  4  5  6  8  9 10
 x[!(x == 11)]  # notice this works
 [1]  1  2  3  4  5  6  7  8  9 10



On Sun, Aug 28, 2011 at 7:20 AM, eyildiz engin.yildizt...@gmail.com wrote:
 You can use 'which' and negative subscripts to remove elements from a vector.

  y-x[-(which(x==0|x==255))]



 chuan_zl wrote:

 Dear All.

 I am Chuan. I am beginner for R.I facing some problem in remove element
 from vector.I have a vector with size 238 element as follow(a part)

 [1] 0 18 24 33 44..[238] 255

 Let the vector label as x,I want remove element 0 and 255.I try use
 such function:

 x[x0  x255]

 However, I am fail since same results are give even try it for many
 times.I also try with shorter vector with 10 element. It is successfully
 resulted. So,want can I do for it. Kindly asking favor for expert here.
 Thank you very much.

 Chuan



 --
 View this message in context: 
 http://r.789695.n4.nabble.com/Asking-Favor-For-Remove-element-with-Particular-Value-In-Vector-tp3772779p3774271.html
 Sent from the R help mailing list archive at Nabble.com.

 __
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 https://stat.ethz.ch/mailman/listinfo/r-help
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 and provide commented, minimal, self-contained, reproducible code.




-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?

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[R] Asking Favor For Remove element with Particular Value In Vector

2011-08-27 Thread chuan_zl
Dear All.

I am Chuan. I am beginner for R.I facing some problem in remove element from
vector.I have a vector with size 238 element as follow(a part)

[1] 0 18 24 33 44..[238] 255

Let the vector label as x,I want remove element 0 and 255.I try use
such function:

x[x0  x255]

However, I am fail since same results are give even try it for many times.I
also try with shorter vector with 10 element. It is successfully resulted.
So,want can I do for it. Kindly asking favor for expert here. Thank you very
much.

Chuan

--
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http://r.789695.n4.nabble.com/Asking-Favor-For-Remove-element-with-Particular-Value-In-Vector-tp3772779p3772779.html
Sent from the R help mailing list archive at Nabble.com.

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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-27 Thread Rainer Schuermann
Not sure whether I understand your question right but here is what I would do:

# Sample data
x - seq(  1, 100, by=6)
x
 [1]  1  7 13 19 25 31 37 43 49 55 61 67 73 79 85 91 97

# remove element with value 19
x - x[ x != 19 ]
x
 [1]  1  7 13 25 31 37 43 49 55 61 67 73 79 85 91 97

If you want to remove values smaller / larger than a certain threshold, your 
way should work well:

# Sample data
x - seq(  1, 100, by=6)
x[9] - 155
x
 [1]   1   7  13  19  25  31  37  43 155  55  61  67  73  79  85  91  97

# Remove elements smaller than 20 or larger than 80:
 x - x[ x  20  x  80 ]
x
 [1] 25 31 37 43 55 61 67 73 79

So there is probably an issue with your data vector - why don't you dput() it?

Rgds,
Rainer


On Saturday 27 August 2011 02:31:29 chuan_zl wrote:
 Dear All.
 
 I am Chuan. I am beginner for R.I facing some problem in remove element from
 vector.I have a vector with size 238 element as follow(a part)
 
 [1] 0 18 24 33 44..[238] 255
 
 Let the vector label as x,I want remove element 0 and 255.I try use
 such function:
 
 x[x0  x255]
 
 However, I am fail since same results are give even try it for many times.I
 also try with shorter vector with 10 element. It is successfully resulted.
 So,want can I do for it. Kindly asking favor for expert here. Thank you very
 much.
 
 Chuan
 
 --
 View this message in context:
 http://r.789695.n4.nabble.com/Asking-Favor-For-Remove-element-with-Particul
 ar-Value-In-Vector-tp3772779p3772779.html Sent from the R help mailing list
 archive at Nabble.com.
 
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Re: [R] Asking Favor For Remove element with Particular Value In Vector

2011-08-27 Thread David Winsemius


On Aug 27, 2011, at 5:31 AM, chuan_zl wrote:


Dear All.

I am Chuan. I am beginner for R.I facing some problem in remove  
element from

vector.I have a vector with size 238 element as follow(a part)

[1] 0 18 24 33 44..[238] 255

Let the vector label as x,I want remove element 0 and 255.I  
try use

such function:

x[x0  x255]


I am not completely clear but it appears that you want to remove the  
first and last elements. You can use negative indexing vectors.


x[ -c(1, length(x) ) ]




However, I am fail


Perhaps your vector is a factor? Try this and see what you get:

str(x)



since same results are give even try it for many times.I
also try with shorter vector with 10 element. It is successfully  
resulted.
So,want can I do for it. Kindly asking favor for expert here. Thank  
you very

much.

Chuan

--



David Winsemius, MD
West Hartford, CT

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