r - R - 2 つのペアワイズ ベクトルを行列に結合する方法

Question

以下の表を考えると：

X = 

        col1    col2    col3
row1    "A"      "A"     "1.0"
row2    "A"      "B"     "0.9"
row3    "A"      "C"     "0.4"
row4    "B"      "A"     "0.9"
row5    "B"      "B"     "1.0"
row6    "B"      "C"     "0.2"
row7    "C"      "A"     "0.4"
row8    "C"      "B"     "0.2"
row9    "C"      "C"     "1.0"

ここで、col3 は、col1 と col2 のエンティティのペア間の相関測定値です。

列名が col1、行名が col2、行列のセルの値が col3 である行列を作成するにはどうすればよいですか?

Answer 1

df <- read.table(textConnection('col1    col2    col3
row1    "A"      "A"     "1.0"
row2    "A"      "B"     "0.9"
row3    "A"      "C"     "0.4"
row4    "B"      "A"     "0.9"
row5    "B"      "B"     "1.0"
row6    "B"      "C"     "0.2"
row7    "C"      "A"     "0.4"
row8    "C"      "B"     "0.2"
row9    "C"      "C"     "1.0"'), header=T)

## fetch row/column indices
rows <- match(df$col1, LETTERS)
cols <- match(df$col2, LETTERS)

## create matrix
m <- matrix(0, nrow=max(rows), ncol=max(cols))

## fill matrix
m[cbind(rows, cols)] <- df$col3

m
#     [,1] [,2] [,3]
#[1,]  1.0  0.9  0.4
#[2,]  0.9  1.0  0.2
#[3,]  0.4  0.2  1.0