On Wed, Jun 25, 2008 at 6:00 PM, Victor Homar <[EMAIL PROTECTED]> wrote:
> > Hi, I'm trying to use sapply to compute the min of several variables, > each > of them stored in data.frames, grouped as a list: > Is it normal that mean() and min() produce different objects dimensions? > it is exactly as documented in ?mean and ?min mean is a generic function which has a separate method for data frames: mean.data.frame <- mean.data.frame function (x, ...) sapply(x, mean, ...) min has no separate method for data frames (so you'll get just one number), but you can define one easily: min.data.frame <- function(...) sapply(..., min) k > str(dats) > List of 5 > $ log20:'data.frame': 83 obs. of 5 variables: > ..$ DATE : int [1:83] 2001081500 2001081512 2001081600 2001081612 > 2001081700 2001081712 2001081800 2001081812 2001081900 2001081912 ... > ..$ logrho: num [1:83] 1.16 -1.30 -1.30 -1.30 -1.30 ... > ..$ w2 : num [1:83] 1.01 1.27 1.24 1.31 1.28 ... > ..$ rms : num [1:83] 5.001 0.630 0.616 0.685 0.655 ... > ..$ maxi : num [1:83] 8.66 3.39 3.83 3.35 3.23 ... > $ log30:'data.frame': 71 obs. of 5 variables: > ..$ DATE : int [1:71] 2001081500 2001081512 2001081600 2001081612 > 2001081700 2001081712 2001081800 2001081812 2001081900 2001081912 ... > ..$ logrho: num [1:71] 1.16 -1.00 -1.00 -1.00 -1.00 ... > ..$ w2 : num [1:71] 1.01 1.27 1.21 1.29 1.27 ... > ..$ rms : num [1:71] 5.001 0.851 0.802 0.877 0.864 ... > ..$ maxi : num [1:71] 8.66 4.57 4.62 4.27 4.47 ... > $ log40:'data.frame': 14 obs. of 5 variables: > ..$ DATE : int [1:14] 2001081500 2001081512 2001081600 2001081612 > 2001081700 2001081712 2001081800 2001081812 2001081900 2001081912 ... > ..$ logrho: num [1:14] 1.16 -0.50 -0.50 -0.50 -0.50 ... > ..$ w2 : num [1:14] 1.01 1.27 1.18 1.23 1.17 ... > ..$ rms : num [1:14] 5.00 1.40 1.26 1.36 1.25 ... > ..$ maxi : num [1:14] 8.66 7.54 6.39 6.68 5.83 ... > $ log50:'data.frame': 69 obs. of 5 variables: > ..$ DATE : int [1:69] 2001081500 2001081512 2001081600 2001081612 > 2001081700 2001081712 2001081800 2001081812 2001081900 2001081912 ... > ..$ logrho: num [1:69] 1.16 -1.50 -1.50 -1.50 -1.50 ... > ..$ w2 : num [1:69] 1.01 1.27 1.25 1.33 1.31 ... > ..$ rms : num [1:69] 5.001 0.516 0.516 0.577 0.554 ... > ..$ maxi : num [1:69] 8.66 2.77 3.44 2.92 3.25 ... > $ log60:'data.frame': 66 obs. of 5 variables: > ..$ DATE : int [1:66] 2001081500 2001081512 2001081600 2001081612 > 2001081700 2001081712 2001081800 2001081812 2001081900 2001081912 ... > ..$ logrho: num [1:66] 1.16 -2.00 -2.00 -2.00 -2.00 ... > ..$ w2 : num [1:66] 1.01 1.27 1.27 1.34 1.34 ... > ..$ rms : num [1:66] 5.001 0.313 0.326 0.371 0.366 ... > ..$ maxi : num [1:66] 8.66 1.68 2.43 2.23 3.85 ... > > sapply(dats,mean) > log20 log30 log40 log50 > log60 > DATE 2.001088e+09 2.001087e+09 2.001082e+09 2.001087e+09 > 2.001086e+09 > logrho -1.270326e+00 -9.695748e-01 -3.816967e-01 -1.461383e+00 > -1.951941e+00 > w2 1.324907e+00 1.283293e+00 1.217808e+00 1.345297e+00 > 1.398435e+00 > rms 7.752963e-01 9.623266e-01 1.636949e+00 6.788993e-01 > 4.810029e-01 > maxi 4.016900e+00 4.466865e+00 6.205573e+00 3.672405e+00 > 2.898055e+00 > > sapply(dats,min) > log20 log30 log40 log50 log60 > -1.3000708 -1.0000960 -0.5000176 -1.5001134 -2.0001350 > Thanks for your help, > Víctor. > -- > ----------------------------------------------------------------------- > Víctor Homar Santaner > Grup de Meteorologia > > Edif. Mateu Orfila Tel: +34 971 17 1376 > Universitat de les Illes Balears Fax: +34 971 17 3426 > 07122 Palma de Mallorca (SPAIN) Email: [EMAIL PROTECTED] > > Knowledge is contagious. Infect truth. > ----------------------------------------------------------------------- > > References > > 1. mailto:[EMAIL PROTECTED] > ______________________________________________ > [email protected] 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. > [[alternative HTML version deleted]]
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