Re: [R] operations on a list

From: <szhan_at_uoguelph.ca>
Date: Fri 09 Dec 2005 - 08:47:53 EST


Hello, Everyone,
I am sorry that my message got truncated due to wrong format. I hope it works now:

Hello, R Users,
I have a list (say listexp) of 10,000 elements, each of which consists of a matrix (5X6). It likes:
$"a"

    trt1rep1 trt1rep2 trt2rep1 trt2rep2 ctlrep1 ctlrep2
[1,] 50 54 98 89 40 45
[2,] 60 65 76 79 34 43
[3,] 86 83 34 45 38 34
[4,] 67 78 88 98 45 41
[5,] 55 59 77 88 56 66
$"b"

   trt1rep1 trt1rep2 trt2rep1 trt2rep2 ctlrep1 ctlrep2
[1,] 55 54 88 86 42 40
[2,] 66 65 86 99 44 48
[3,] 80 86 44 55 38 44
[4,] 77 78 98 92 35 41
[5,] 50 53 87 88 46 56

.

I want to perform some operations on the list and then got a new list(say expeffect) like this:
1. first average two replicates for each row in the matrix shown above (like for treatment 1 using (trt1rep1+trt1rep2)/2) and get one value for each treatment/control
2. then subtract average value of the control from the each treatment and get one value for the treatment effect for each row in the matrix shown above 3. make a new list (say trteffect) with 2 elements (trt1 and trt2), each of which consists of a matrix (10,000X5)with a row name same with old list's element name, a column name corresponding to the row name of old list's matrix like:
$"trt1"

     [,1]    [,2]    [,3]    [,4]     [,5]
a    9.5     24       48.5    29.5     -4
b   13.5     19.5     42      39.5      0.5
.

$"trt2"

     [,1]    [,2]    [,3]    [,4]     [,5]
a    51      39      3.5     50       21.5
b    46      46.5    8.5     57       30.5
.

Could you please help me to make this new list (expeffect)? Thank you in advance!
Joshua



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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Dec 09 08:54:31 2005

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