R help - Nov 2005 - Calculating the 2th power of a vector

Hi every body ,
  
  I simply want to calculate the 2th power of a vector without changing the sign
of values. How it is possible in R ?
  
  Thanks a lot for any idea.
  Amir
  

		
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Amir Safari wrote:
>   I simply want to calculate the 2th power of a vector without changing the
sign of values. How it is possible in R ?

I'm not quite sure what you mean, but maybe:

  > x
  [1] -4 -3 -2 -1  0  1  2  3  4
  > x^2
  [1] 16  9  4  1  0  1  4  9 16

  - that obviously makes everything positive (unless any of x are complex!)

  So do:

  > x^2 * sign(x)
  [1] -16  -9  -4  -1   0   1   4   9  16

  to keep the sign. Is that what you want?

Baz

?sign

 > x <- rnorm(20)

 > x
  [1]  0.42775501  0.77370847 -2.39860006  1.75882148
  [5] -0.08231117 -0.11121029  0.93786747 -1.73588115
  [9]  0.92659445 -0.59913052  0.16399931 -1.08586327
[13]  0.30092859 -0.30683075 -0.87974642  1.65483615
[17] -0.05118100  0.70005335  1.86429650  1.12937824

 > x^2
  [1] 0.182974345 0.598624790 5.753282243 3.093453001
  [5] 0.006775129 0.012367728 0.879595393 3.013283374
  [9] 0.858577271 0.358957383 0.026895773 1.179099031
[13] 0.090558015 0.094145111 0.773953771 2.738482695
[17] 0.002619495 0.490074687 3.475601451 1.275495200

 > x^2*sign(x)
  [1]  0.182974345  0.598624790 -5.753282243
  [4]  3.093453001 -0.006775129 -0.012367728
  [7]  0.879595393 -3.013283374  0.858577271
[10] -0.358957383  0.026895773 -1.179099031
[13]  0.090558015 -0.094145111 -0.773953771
[16]  2.738482695 -0.002619495  0.490074687
[19]  3.475601451  1.275495200

Amir Safari wrote:
>  
>   
>   Hi every body ,
>   
>   I simply want to calculate the 2th power of a vector without changing the
sign of values. How it is possible in R ?
>   
>   Thanks a lot for any idea.
>   Amir
>   
> 
> 		
> ---------------------------------
> 
> 	[[alternative HTML version deleted]]
> 
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