Indexing Data then transforming into a matrix


#1

I have a 16384 x 1 matrix of data.

I am trying to index every 256 rows and get a resulting matrix of dimension 256 x 64.

Below is my attempt to index the data.

###transforming data

for (i in 1:64);

data.i <- testset[(1:256)*i,]

I am a little bit confused on loops and how I would index the rows then combine then column by column.


#2

Try it this way

testset <- seq(1:16384)
testset <- matrix(testset, nrow = 256, byrow = TRUE)
head(testset)
#>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13]
#> [1,]    1    2    3    4    5    6    7    8    9    10    11    12    13
#> [2,]   65   66   67   68   69   70   71   72   73    74    75    76    77
#> [3,]  129  130  131  132  133  134  135  136  137   138   139   140   141
#> [4,]  193  194  195  196  197  198  199  200  201   202   203   204   205
#> [5,]  257  258  259  260  261  262  263  264  265   266   267   268   269
#> [6,]  321  322  323  324  325  326  327  328  329   330   331   332   333
#>      [,14] [,15] [,16] [,17] [,18] [,19] [,20] [,21] [,22] [,23] [,24]
#> [1,]    14    15    16    17    18    19    20    21    22    23    24
#> [2,]    78    79    80    81    82    83    84    85    86    87    88
#> [3,]   142   143   144   145   146   147   148   149   150   151   152
#> [4,]   206   207   208   209   210   211   212   213   214   215   216
#> [5,]   270   271   272   273   274   275   276   277   278   279   280
#> [6,]   334   335   336   337   338   339   340   341   342   343   344
#>      [,25] [,26] [,27] [,28] [,29] [,30] [,31] [,32] [,33] [,34] [,35]
#> [1,]    25    26    27    28    29    30    31    32    33    34    35
#> [2,]    89    90    91    92    93    94    95    96    97    98    99
#> [3,]   153   154   155   156   157   158   159   160   161   162   163
#> [4,]   217   218   219   220   221   222   223   224   225   226   227
#> [5,]   281   282   283   284   285   286   287   288   289   290   291
#> [6,]   345   346   347   348   349   350   351   352   353   354   355
#>      [,36] [,37] [,38] [,39] [,40] [,41] [,42] [,43] [,44] [,45] [,46]
#> [1,]    36    37    38    39    40    41    42    43    44    45    46
#> [2,]   100   101   102   103   104   105   106   107   108   109   110
#> [3,]   164   165   166   167   168   169   170   171   172   173   174
#> [4,]   228   229   230   231   232   233   234   235   236   237   238
#> [5,]   292   293   294   295   296   297   298   299   300   301   302
#> [6,]   356   357   358   359   360   361   362   363   364   365   366
#>      [,47] [,48] [,49] [,50] [,51] [,52] [,53] [,54] [,55] [,56] [,57]
#> [1,]    47    48    49    50    51    52    53    54    55    56    57
#> [2,]   111   112   113   114   115   116   117   118   119   120   121
#> [3,]   175   176   177   178   179   180   181   182   183   184   185
#> [4,]   239   240   241   242   243   244   245   246   247   248   249
#> [5,]   303   304   305   306   307   308   309   310   311   312   313
#> [6,]   367   368   369   370   371   372   373   374   375   376   377
#>      [,58] [,59] [,60] [,61] [,62] [,63] [,64]
#> [1,]    58    59    60    61    62    63    64
#> [2,]   122   123   124   125   126   127   128
#> [3,]   186   187   188   189   190   191   192
#> [4,]   250   251   252   253   254   255   256
#> [5,]   314   315   316   317   318   319   320
#> [6,]   378   379   380   381   382   383   384

Created on 2019-01-17 by the reprex package (v0.2.1)

flodel: https://stackoverflow.com/questions/17752830/r-reshape-a-vector-into-multiple-columns


#3

Thank you that worked.


closed #4

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