[R] Odp: A question on List

[Petr PIKAL]

Hi

 mapply("*", vect, mat, SIMPLIFY=F)

Regards
Petr

r-help-bounces at r-project.org napsal dne 21.08.2009 10:53:19:

> 
> Suppose I have following list :
> 
> mat <- vector("list")
> for (i in 1:4) mat[[i]] <- matrix(rnorm(25),5)
> mat
> 
> > mat
> [[1]]
>             [,1]       [,2]       [,3]       [,4]       [,5]
> [1,] -1.27171814 -0.8087277 -0.4771356  0.6001265  0.9842248
> [2,] -1.37337445  1.0754536 -1.6304287 -0.6854075 -0.6029390
> [3,] -0.32393457 -0.8933633 -0.9077967  0.9738039 -3.0220266
> [4,] -1.22184968 -1.2571625 -0.4064736 -1.6686981 -0.4896512
> [5,] -0.09333244  1.4880530  1.6410411 -0.5489993  1.0939736
> 
> [[2]]
>            [,1]       [,2]       [,3]       [,4]       [,5]
> [1,] -1.0139178 -0.4817983 -0.2141111  0.1649356  1.7750268
> [2,]  1.5544890  0.6345386  1.6307417 -2.0887206  1.8299279
> [3,] -0.3575260 -0.6669547  0.5960779 -1.1091696 -0.2831409
> [4,]  0.7742701  0.8313172  0.4178063 -2.5993914 -0.9920140
> [5,] -0.6238547  0.8777678 -1.4249051 -0.4793574  0.5290309
> 
> [[3]]
>            [,1]       [,2]         [,3]       [,4]        [,5]
> [1,] -1.2833578  0.2271013 -1.605616640  0.3379672  0.86307678
> [2,]  0.8928252 -0.2826024 -0.294600779  0.3659292 -0.06884467
> [3,] -0.8237363  1.2258510  1.091578624  1.6907392 -0.42073560
> [4,] -0.2537396  0.3662041  0.009558159  1.2127068 -1.14449393
> [5,] -0.5001592  0.5390412  0.372628875 -0.9434233 -0.52022201
> 
> [[4]]
>             [,1]         [,2]        [,3]       [,4]       [,5]
> [1,]  0.55638191  2.000902039 -0.40155111  0.6214637  0.4044958
> [2,]  0.06705861 -0.005629049  0.05144204  0.4910031 -0.2711823
> [3,] -2.07173018 -0.210809259  0.22680564  0.5624870 -2.1322234
> [4,]  0.04591303 -0.735466145 -0.13164334 -1.8873585 -1.2711131
> [5,]  0.67454754  0.911601123  1.34304395  2.2798986 -0.5136242
> 
> Define another vector :
> 
> vect <- rnorm(4)
> 
> 
> Now I want to do following calculation
> 
> for (i in 1:4) mat[[i]] <- mat[[i]] * vect[i]
> mat
> 
> 
> My question is, can I do previous calculation without having "for" loop?
> 
> Thanks
> 
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