[R] Problem with "apply"
Marc Schwartz
marc_schwartz at me.com
Wed Apr 22 21:11:33 CEST 2009
The cut() function will do what you want in a vectorized fashion. See ?
cut
However, that being said, I would strongly advise that you read
Frank's page on the categorizing of continuous variables:
http://biostat.mc.vanderbilt.edu/twiki/bin/view/Main/CatContinuous
before you proceed.
HTH,
Marc Schwartz
On Apr 22, 2009, at 1:56 PM, Alan Cohen wrote:
> Hi R users,
>
> I am trying to assign ages to age classes for a large data set
> (123,000 records), and using a for-loop was too slow, so I wrote a
> function and used apply. However, the function does not properly
> assign the first two classes (the rest are fine). It appears that
> when age is one digit, it does not get assigned properly.
>
> I tried to provide a small-scale work-up (at the end of the email)
> but it does not reproduce the problem; the best I can do is to
> provide my code and the output below. As you can see, I've
> confirmed that age is numeric, that all values are integers, and
> that pieces of the code work independently. Any thoughts would be
> appreciated.
>
> To add to the mystery, depending which rows of my data set I select,
> I get different problems. mds[1:100,] gives the problem above, as
> do mds[100:200,] , mds[150:250,] and mds[10000:10100,]. However,
> with mds[200:300,], mds[250:350,] and mds[1000:1100,], only ages
> with 3 digits are correctly assigned - all ages <100 are returned as
> NA.
>
> I'm using R v 2.8.1 on Windows XP.
>
> Cheers,
> Alan Cohen
> Centre for Global Health Research,
> Toronto,ON
>
>> ageassign <- function(x){
> + y <- NA
> + if (x[11] %in% c(0:4)) {y <- "0-4"}
> + else if (x[11] %in% c(5:14)) {y <- "5-14" }
> + else if (x[11] %in% c(15:29)) {y <- "15-29" }
> + else if (x[11] %in% c(30:69)) {y <- "30-69"}
> + else if (x[11] %in% c(70:79)) {y <- "70-79"}
> + else if (x[11] %in% c(80:125)) {y <- "80+"}
> + return(y)
> + }
>> jj <- apply(mds[1:100,],1,FUN=ageassign)
>> jj
> 1 2 3 4 5 6 7 8
> 9 10 11 12 13
> NA "80+" "30-69" "30-69" "80+" NA "30-69" "30-69"
> "70-79" "15-29" "15-29" "30-69" "70-79"
> 14 15 16 17 18 19 20 21
> 22 23 24 25 26
> "80+" NA "30-69" "30-69" "30-69" "80+" "80+" "15-29"
> "70-79" "30-69" "70-79" "70-79" "30-69"
> 27 28 29 30 31 32 33 34
> 35 36 37 38 39
> "70-79" "80+" NA "80+" "70-79" NA "15-29" "15-29"
> NA NA "70-79" "30-69" "30-69"
> 40 41 42 43 44 45 46 47
> 48 49 50 51 52
> "70-79" "30-69" "30-69" "30-69" "70-79" "30-69" "30-69" "70-79"
> "15-29" "30-69" NA "15-29" "30-69"
> 53 54 55 56 57 58 59 60
> 61 62 63 64 65
> "30-69" NA "70-79" "30-69" "30-69" "30-69" "30-69" "15-29"
> "30-69" "30-69" "70-79" "30-69" NA
> 66 67 68 69 70 71 72 73
> 74 75 76 77 78
> "30-69" "30-69" "30-69" "30-69" "30-69" "80+" "30-69" "80+"
> "70-79" "30-69" "30-69" "30-69" NA
> 79 80 81 82 83 84 85 86
> 87 88 89 90 91
> "30-69" "30-69" "30-69" NA "80+" "30-69" "30-69" "30-69"
> NA "15-29" "30-69" "30-69" "30-69"
> 92 93 94 95 96 97 98 99 100
> "30-69" "30-69" "30-69" "30-69" "70-79" "30-69" "30-69" "30-69"
> "30-69"
>> mds[1:100,11]
> [1] 3 82 40 35 82 1 37 57 71 22 21 52 73 86 1 43 60 63 84 88 29
> 73 69 75 73 43 75 83 4 83 77 1 27
> [34] 15 1 6 76 51 45 71 54 64 69 70 48 38 74 26 37 4 18 63 59 8
> 78 63 67 62 50 21 66 69 75 57 4 50
> [67] 58 60 61 62 83 69 92 75 30 49 69 1 69 63 69 0 93 64 59 69 2
> 25 32 60 66 67 54 53 64 79 59 49 59
> [100] 64
>> table(mds[,11])
>
> 0 1 2 3 4 5 6 7 8 9 10 11 12
> 13 14 15 16 17 18 19
> 3123 6441 3856 2884 1968 1615 1386 1088 1098 721 943 681 511
> 380 426 835 571 555 719 653
> 20 21 22 23 24 25 26 27 28 29 30 31 32
> 33 34 35 36 37 38 39
> 879 715 672 631 655 773 680 713 769 538 685 566 729
> 702 652 766 683 723 821 675
> 40 41 42 43 44 45 46 47 48 49 50 51 52
> 53 54 55 56 57 58 59
> 774 650 908 892 784 925 781 1043 1161 924 1087 827 1261 1356
> 1297 1272 1277 1614 1831 1523
> 60 61 62 63 64 65 66 67 68 69 70 71 72
> 73 74 75 76 77 78 79
> 1702 1251 1954 2157 1901 2090 1874 2705 3085 2529 2488 1777 2701
> 2586 2308 2020 1801 2269 2486 1856
> 80 81 82 83 84 85 86 87 88 89 90 91 92
> 93 94 95 96 97 98 99
> 1762 1047 1413 1326 967 1013 753 870 884 531 601 277 364
> 301 193 288 149 174 169 470
> 100 101 102 103 104 105 106 107 108 114 115 117 118
> 120 125
> 15 2 5 7 2 4 1 1 2 1 1 2 2
> 2 1
>> mode(mds[,11])
> [1] "numeric"
>
>> mds[1,11] %in% c(0:4)
> [1] TRUE
>> if (mds[1,11] %in% c(0:4)) {y <- "0-4"}
>> y
> [1] "0-4"
>
>> xx <- matrix(trunc(runif(30,0,125)),15,2)
>> aassign <- function(x){
> + y <- NA
> + if (x[2] %in% c(0:4)) {y <- "0-4"}
> + else if (x[2] %in% c(5:14)) {y <- "5-14" }
> + else if (x[2] %in% c(15:29)) {y <- "15-29" }
> + else if (x[2] %in% c(30:69)) {y <- "30-69"}
> + else if (x[2] %in% c(70:79)) {y <- "70-79"}
> + else if (x[2] %in% c(80:125)) {y <- "80+"}
> + return(y)
> + }
>> jj <- apply(xx,1,FUN=aassign)
>> t(xx)
> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,
> 13] [,14] [,15]
> [1,] 23 98 107 94 76 103 106 40 66 11 109
> 101 96 37 18
> [2,] 11 57 58 91 43 123 103 77 4 79 64
> 10 8 105 76
>> jj
> [1] "5-14" "30-69" "30-69" "80+" "30-69" "80+" "80+" "70-79"
> "0-4" "70-79" "30-69" "5-14"
> [13] "5-14" "80+" "70-79"
>>
>
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