[R] Re categorizing components of varaibles

[JS Huang]

Hi,

  Here I use the data.frame b as an example to show how it can be
accomplished.  The sixth column of b has values 6 through 996 by an
increment of 10.  The statement
sapply(b[,6],function(x)if(x==6){0}else{if(x==996){2}else{1}}) assigns 0 to
6, 2 to 996 and 1 to the rest in column 6.  In your case you may use

sapply(b[,6],function(x)if(x==24){2}else{if(x==26){3}else{1}})  

(Note: did you forget to assign a value to 25?)

> a <- matrix(1:1000, ncol=10, byrow=TRUE)
> b <- data.frame(a)
> b[,6] <- sapply(b[,6],function(x)if(x==6){0}else{if(x==996){2}else{1}})
> b <- data.frame(a)
> b[,6]
  [1]   6  16  26  36  46  56  66  76  86  96 106 116 126 136 146 156 166
176 186 196 206 216 226 236
 [25] 246 256 266 276 286 296 306 316 326 336 346 356 366 376 386 396 406
416 426 436 446 456 466 476
 [49] 486 496 506 516 526 536 546 556 566 576 586 596 606 616 626 636 646
656 666 676 686 696 706 716
 [73] 726 736 746 756 766 776 786 796 806 816 826 836 846 856 866 876 886
896 906 916 926 936 946 956
 [97] 966 976 986 996
> b[,6] <- sapply(b[,6],function(x)if(x==6){0}else{if(x==996){2}else{1}})
> b[,6]
  [1] 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1
 [50] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1
 [99] 1 2 



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