[R] how to recover a list structure
Dimitris Rizopoulos
d.rizopoulos at erasmusmc.nl
Sun Feb 22 10:44:13 CET 2009
another option is to use relist(), e.g.,
x <- list(a=runif(10), b=runif(30), c=runif(25))
x <- as.relistable(x)
ux <- unlist(x)
ux[order(ux)[1:5]] <- -1
relist(ux)
Best,
Dimitris
jim holtman wrote:
> Here is one way that might work.
>
> x <- list(a=runif(10), b=runif(30), c=runif(25))
> # unlist and then construct a factor to put them back together
> x.u <- unlist(x)
> x.f <- unlist(mapply(rep, names(x), sapply(x, length)))
> # find the lowest 5 values and set to -1
> x.u[order(x.u)[1:5]] <- -1
> # put back together
> split(x.u, x.f)
>
>
> On Sat, Feb 21, 2009 at 11:51 PM, <mauede at alice.it> wrote:
>> I am experiencing some problems at working with lists at high level.
>> In the following "coef" contains the original DWT coefficients organized in a list.
>> Thorugh applying the following two commands:
>> coef.abs <- lapply(unlist(coef,recursive=FALSE,use.names =TRUE),abs)
>> coef.abs.sorted <- sort(unlist(coef.abs),decreasing=TRUE)
>> I get vector "coef.abs.sorted" containing the coefficients absolute value ordered by decreasing magnitude, whose first 10 elements I set to zero after applying an iterative math formula (telling me how many coefficient values to spare).
>> My problem is setting to zero the correspondent coefficients in the original "coef" list so as to reconstruct the signal from the depleted coefficients set, given that the above operations have erased the list structure. I can get the labels of the coefficients that have to be zeroed ... but the names of vector "coef.abs.sorted" elements differes from the original "coef" list elements as shown in the following:
>> > names(coef.abs.sorted[1:10])
>> [1] "d6.d6(0)" "d5.d5(2)" "d5.d5(0)" "d4.d4(2)" "d5.d5(1)" "d4.d4(1)" "d4.d4(6)" "d4.d4(5)" "d4.d4(3)"
>> [10] "d3.d3(12)"
>> I wonder if there exists a high level command to set to zero respectively the coefficients in list "coef":
>> - Level=6, Oscillation-Number=0
>> - Level=5, Oscillation-Number=0,1,2
>> - Level=4, Oscillation-Number=1,2,3,5.6
>> - Level=3, Oscillation-Number=12
>>
>>
>>> coef
>> $d1
>> d1(0) d1(1) d1(2) d1(3) d1(4) d1(5) d1(6) d1(7)
>> 1.075111e-02 -4.777441e-03 -2.775026e-03 2.011722e-03 -2.376611e-02 -1.574422e-03 -2.810372e-02 8.542393e-03
>> d1(8) d1(9) d1(10) d1(11) d1(12) d1(13) d1(14) d1(15)
>> -1.754845e-02 -7.363856e-04 3.123922e-03 1.053743e-02 -1.014095e-02 1.059210e-02 -4.152311e-03 -7.320749e-04
>> d1(16) d1(17) d1(18) d1(19) d1(20) d1(21) d1(22) d1(23)
>> -3.680064e-03 5.620248e-03 -2.251741e-03 -1.454674e-02 1.891275e-02 2.092009e-03 -1.286729e-02 9.037282e-03
>> d1(24) d1(25) d1(26) d1(27) d1(28) d1(29) d1(30) d1(31)
>> -1.027137e-02 1.014230e-02 -2.175260e-03 -1.689383e-03 -2.016800e-03 3.984632e-03 -1.563781e-03 -3.801979e-03
>> d1(32) d1(33) d1(34) d1(35) d1(36) d1(37) d1(38) d1(39)
>> 6.976144e-04 1.048419e-03 -1.319865e-02 -8.368520e-04 6.618890e-03 -5.835673e-03 8.721318e-03 2.018621e-02
>> d1(40) d1(41) d1(42) d1(43) d1(44) d1(45) d1(46) d1(47)
>> -3.329934e-03 -4.823901e-03 2.957486e-02 -2.887600e-02 2.500062e-02 -2.207839e-02 1.516034e-02 4.328945e-05
>> d1(48) d1(49) d1(50) d1(51) d1(52) d1(53) d1(54) d1(55)
>> 1.605634e-02 -2.360298e-02 7.875788e-03 -4.129065e-03 -1.014460e-02 -2.676679e-03 -9.953614e-03 -8.844977e-03
>> d1(56) d1(57) d1(58) d1(59)
>> -2.141513e-02 -7.405836e-03 -5.078857e-03 8.480675e-04
>>
>> $d2
>> d2(0) d2(1) d2(2) d2(3) d2(4) d2(5) d2(6) d2(7) d2(8)
>> 0.033393680 0.015767682 -0.006008297 0.016899336 0.006661543 0.005297962 -0.005782728 -0.009358879 -0.012128449
>> d2(9) d2(10) d2(11) d2(12) d2(13) d2(14) d2(15) d2(16) d2(17)
>> -0.014097771 0.003439004 -0.010154074 0.031203264 -0.057290615 0.004552577 0.061358997 -0.040730889 0.004064522
>> d2(18) d2(19) d2(20) d2(21) d2(22) d2(23) d2(24) d2(25) d2(26)
>> -0.007208508 0.010426952 0.003855540 -0.011492580 0.035028591 0.029604957 -0.020069126 -0.018983905 -0.033710992
>> d2(27) d2(28) d2(29)
>> 0.035848240 -0.014716622 0.008372893
>>
>> $d3
>> d3(0) d3(1) d3(2) d3(3) d3(4) d3(5) d3(6) d3(7) d3(8)
>> 0.020437693 -0.023658475 0.033448175 0.009689787 0.024750901 0.040022643 0.016532575 -0.035730498 -0.048828011
>> d3(9) d3(10) d3(11) d3(12) d3(13) d3(14)
>> -0.012357469 -0.042282285 0.010908775 -0.061393069 0.058384786 -0.036842060
>>
>> $d4
>> d4(0) d4(1) d4(2) d4(3) d4(4) d4(5) d4(6)
>> 0.05419644 -0.23596007 0.84412709 0.06639234 0.02718491 0.15101792 -0.18101631
>>
>> $d5
>> d5(0) d5(1) d5(2)
>> 2.3514158 -0.4952582 -2.5589658
>>
>> $d6
>> d6(0)
>> -5.643476
>>
>>
>>> coef.abs.sorted
>> d6.d6(0) d5.d5(2) d5.d5(0) d4.d4(2) d5.d5(1) d4.d4(1) d4.d4(6) d4.d4(5) d4.d4(3)
>> 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00
>> d3.d3(12) d2.d2(15) d3.d3(13) d2.d2(13) d4.d4(0) d3.d3(8) d3.d3(10) d2.d2(16) d3.d3(5)
>> 0.000000e+00 6.135900e-02 5.838479e-02 5.729061e-02 5.419644e-02 4.882801e-02 4.228228e-02 4.073089e-02 4.002264e-02
>> d3.d3(14) d2.d2(27) d3.d3(7) d2.d2(22) d2.d2(26) d3.d3(2) d2.d2(0) d2.d2(12) d2.d2(23)
>> 3.684206e-02 3.584824e-02 3.573050e-02 3.502859e-02 3.371099e-02 3.344818e-02 3.339368e-02 3.120326e-02 2.960496e-02
>> d1.d1(42) d1.d1(43) d1.d1(6) d4.d4(4) d1.d1(44) d3.d3(4) d1.d1(4) d3.d3(1) d1.d1(49)
>> 2.957486e-02 2.887600e-02 2.810372e-02 2.718491e-02 2.500062e-02 2.475090e-02 2.376611e-02 2.365848e-02 2.360298e-02
>> d1.d1(45) d1.d1(56) d3.d3(0) d1.d1(39) d2.d2(24) d2.d2(25) d1.d1(20) d1.d1(8) d2.d2(3)
>> 2.207839e-02 2.141513e-02 2.043769e-02 2.018621e-02 2.006913e-02 1.898390e-02 1.891275e-02 1.754845e-02 1.689934e-02
>> d3.d3(6) d1.d1(48) d2.d2(1) d1.d1(46) d2.d2(28) d1.d1(19) d2.d2(9) d1.d1(34) d1.d1(22)
>> 1.653258e-02 1.605634e-02 1.576768e-02 1.516034e-02 1.471662e-02 1.454674e-02 1.409777e-02 1.319865e-02 1.286729e-02
>> d3.d3(9) d2.d2(8) d2.d2(21) d3.d3(11) d1.d1(0) d1.d1(13) d1.d1(11) d2.d2(19) d1.d1(24)
>> 1.235747e-02 1.212845e-02 1.149258e-02 1.090878e-02 1.075111e-02 1.059210e-02 1.053743e-02 1.042695e-02 1.027137e-02
>> d2.d2(11) d1.d1(52) d1.d1(25) d1.d1(12) d1.d1(54) d3.d3(3) d2.d2(7) d1.d1(23) d1.d1(55)
>> 1.015407e-02 1.014460e-02 1.014230e-02 1.014095e-02 9.953614e-03 9.689787e-03 9.358879e-03 9.037282e-03 8.844977e-03
>> d1.d1(38) d1.d1(7) d2.d2(29) d1.d1(50) d1.d1(57) d2.d2(18) d2.d2(4) d1.d1(36) d2.d2(2)
>> 8.721318e-03 8.542393e-03 8.372893e-03 7.875788e-03 7.405836e-03 7.208508e-03 6.661543e-03 6.618890e-03 6.008297e-03
>> d1.d1(37) d2.d2(6) d1.d1(17) d2.d2(5) d1.d1(58) d1.d1(41) d1.d1(1) d2.d2(14) d1.d1(14)
>> 5.835673e-03 5.782728e-03 5.620248e-03 5.297962e-03 5.078857e-03 4.823901e-03 4.777441e-03 4.552577e-03 4.152311e-03
>> d1.d1(51) d2.d2(17) d1.d1(29) d2.d2(20) d1.d1(31) d1.d1(16) d2.d2(10) d1.d1(40) d1.d1(10)
>> 4.129065e-03 4.064522e-03 3.984632e-03 3.855540e-03 3.801979e-03 3.680064e-03 3.439004e-03 3.329934e-03 3.123922e-03
>> d1.d1(2) d1.d1(53) d1.d1(18) d1.d1(26) d1.d1(21) d1.d1(28) d1.d1(3) d1.d1(27) d1.d1(5)
>> 2.775026e-03 2.676679e-03 2.251741e-03 2.175260e-03 2.092009e-03 2.016800e-03 2.011722e-03 1.689383e-03 1.574422e-03
>> d1.d1(30) d1.d1(33) d1.d1(59) d1.d1(35) d1.d1(9) d1.d1(15) d1.d1(32) d1.d1(47)
>> 1.563781e-03 1.048419e-03 8.480675e-04 8.368520e-04 7.363856e-04 7.320749e-04 6.976144e-04 4.328945e-05
>>
>>
>> Thank you so much.
>> Maura
>>
>>
>>
>>
>>
>>
>>
>> tutti i telefonini TIM!
>>
>>
>> [[alternative HTML version deleted]]
>>
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>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
>
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
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