[R] Subtracting a matrix 1x28 from a scalar

Rui Barradas ruipbarradas at sapo.pt
Mon May 7 21:44:51 CEST 2012


Hello,


meredith wrote
> 
> Afternoon-
>   I am trying to subtract a matrix, basically a vector of 28 values, each
> by the same number to account for differences in regression fitting. I am
> taking the 1x28 and minus it by the mean value of the matrix, each number.
> The result I receive is a 1X29 matrix. Does anyone know why the result has
> an extra value?
> 
>> lffeb_march
>  [1] 6.588926 7.663877 6.917706 6.824374 7.029973 6.549651 6.517671
> 6.070738 5.916202
> [10] 6.993933 6.091310 7.313220 5.135798 6.762730 6.381816 7.999679
> 6.851185 5.799093
> [19] 7.774856 6.956545 8.218787 8.218787 7.549609 7.222566 7.170120
> 6.173786 5.075174
> [28] 4.700480 6.672033 5.198497 4.867534 7.170120 6.131226 6.802395 
>> meanf_fm<-mean(lffeb_march)
>> X3_fm<-(lffeb_march-meanf_fm)
>> X3_fm
>  [1] -0.03784990  1.03710088  0.29092923  0.19759729  0.40319653
> -0.07712564 -0.10910511
>  [8] -0.55603865 -0.71057432  0.36715660 -0.53546650  0.68644401
> -1.49097794  0.13595313
> [15] -0.24496036  1.37290220  0.22440855 -0.82768372  1.14807939 
> 0.32976906  1.59201078
> [22]  1.59201078  0.92283279  0.59578964  0.54334317 -0.45299027
> -1.55160256 -1.92629601
> [29]  0.04525657 -1.42827935 -1.75924193  0.54334317 -0.49554989 
> 0.17561839
> 
> Thanks for the help
> Meredith
> 

Each of your two vectors has 34 elements, not 28 and 29.
And when I suntract mean( lffeb_march) from  lffeb_march (the first vector)
I get a vector close but not equal to your second vector. It's off by 1e-7
or 1e-8, mostly 1e-7.

The function all.equal() gives
[1] "Mean relative difference: 3.568577e-07"

So, please, revise your results.

(You should use dput(lffeb_march) to post your data.)

Hope this helps,

Rui Barradas


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