On Jun 11, 2009, at 2:53 PM, Payam Minoofar wrote:
Hello everyone,
I have a couple of fairly simple questions (I hope) the answers to
which I cannot find through the documentation at the moment.
1. I would like to delete the a row from a matrix if a certain
elimination criterion is met. I am familiar with x <- x[-7,] (to
remove row 7, for example). Are there any other means of removing an
entire row?
?which # useful for converting logical vectors into argument for
functions that require numerics
M10 <- matrix(1:100, nrow = 10)
# find row with 63
which( sapply( 1:10, function(x) 63 %in% M10[x, ]) )
[1] 3
M10[-which( sapply( 1:10, function(x) 63 %in% M10[x, ]) ), ] #
remove row with 63
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 1 11 21 31 41 51 61 71 81 91
[2,] 2 12 22 32 42 52 62 72 82 92
[3,] 4 14 24 34 44 54 64 74 84 94
[4,] 5 15 25 35 45 55 65 75 85 95
[5,] 6 16 26 36 46 56 66 76 86 96
[6,] 7 17 27 37 47 57 67 77 87 97
[7,] 8 18 28 38 48 58 68 78 88 98
[8,] 9 19 29 39 49 59 69 79 89 99
[9,] 10 20 30 40 50 60 70 80 90 100
2. Is there a single command that will rename the index of each
row to match the row number once a row has been deleted. For
example, when row 7 is deleted above, the old row 8 is now row 7,
but the row name is still "8". I have figured out how to assign a
sequence vector to the row names, but I am wondering if there is a
built-in command that does the same thing. (I.e., change the name of
row 7 to "7" from "8".)
Thank you very much.
Payam
--
Payam Minoofar, Ph.D.
Scientist
Meissner Filtration Products
4181 Calle Tesoro
Camarillo, CA 93012
USA
+1 805 388 9911
+1 805 388 5948 fax
payam.minoo...@meissner.com
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