CODEWITHSUNDEEP
rmatrix
user3472591
user3472591

Reputation: 41

How to transform matrix into matrix with more columns in r

I am trying to transform a matrix with two columns into a matrix of another form. The thing that combines the two, is the numbering from 1:5. Does anyone have a hint on an easier way of doing the following?

Thanks in advance This is my code

data <- matrix(c(rep(1:5,6),101:130),byrow=FALSE,ncol=2)
    data
         [,1] [,2]
 [1,]    1  101
 [2,]    2  102
 [3,]    3  103
 [4,]    4  104
 [5,]    5  105
 [6,]    1  106
 [7,]    2  107
 [8,]    3  108
 [9,]    4  109
[10,]    5  110
[11,]    1  111
[12,]    2  112
[13,]    3  113
[14,]    4  114
[15,]    5  115
[16,]    1  116
[17,]    2  117
[18,]    3  118
[19,]    4  119
[20,]    5  120
[21,]    1  121
[22,]    2  122
[23,]    3  123
[24,]    4  124
[25,]    5  125
[26,]    1  126
[27,]    2  127
[28,]    3  128
[29,]    4  129
[30,]    5  130

data.2 <- matrix(data[,2],ncol=6)
data.2
      [,1] [,2] [,3] [,4] [,5] [,6]
[1,]  101  106  111  116  121  126
[2,]  102  107  112  117  122  127
[3,]  103  108  113  118  123  128
[4,]  104  109  114  119  124  129
[5,]  105  110  115  120  125  130
rownames(data.2) <- c(1:5)
data.2
  [,1] [,2] [,3] [,4] [,5] [,6]
1  101  106  111  116  121  126
2  102  107  112  117  122  127
3  103  108  113  118  123  128
4  104  109  114  119  124  129
5  105  110  115  120  125  130

Upvotes: 0

Views: 78

Answers (2)

Roland
Roland

Reputation: 132626

data <- matrix(c(rep(1:5,6),101:130),byrow=FALSE,ncol=2)

res <- t(unstack(data.frame(data), X2~X1))
#clean up rownames:
rownames(res) <- gsub("X", "", rownames(res))

#  [,1] [,2] [,3] [,4] [,5] [,6]
#1  101  106  111  116  121  126
#2  102  107  112  117  122  127
#3  103  108  113  118  123  128
#4  104  109  114  119  124  129
#5  105  110  115  120  125  130

Upvotes: 1

bartektartanus
bartektartanus

Reputation: 16080

If you are sure that first column is always 1:5 repeated n'th times then you could just simply create matrix from second column:

matrix(data[,2], nrow=5)

Or you can sort matrix by first column:

matrix(data[order(data[,1]),2], nrow=5, byrow=TRUE)

I think that @Roland idea with unstack is better than my solutions :)

Upvotes: 0

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