r - 使用模式更改矩阵中的多个值

Question

我的输入矩阵

set.seed(123)
m1 <- matrix(sample(letters, 50, replace=TRUE), 5) 

在这里，我想按照 4 个字母差异的模式将字母替换为“A”、“B”、“C”、“D”。即“A”应替换字母“a”，“e”，“i”，“m”，“q”，“u”，“y”，“B”替换“b”，“f”，“j” ，....ETC。

我试过了

replace(m1, c("a","e","i","m","q", "u", "y"), "A")

这是不正确的。

Answer 1

这是一种使用模运算的方法:

matrix(toupper(letters)[((match(m1, letters) - 1) %% 4) + 1], ncol=ncol(m1))

#      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
# [1,] "D"  "B"  "A"  "D"  "D"  "C"  "B"  "A"  "D"  "D"  
# [2,] "A"  "B"  "D"  "C"  "C"  "C"  "D"  "D"  "C"  "C"  
# [3,] "C"  "D"  "B"  "B"  "A"  "D"  "B"  "B"  "C"  "A"  
# [4,] "C"  "C"  "C"  "A"  "B"  "D"  "A"  "A"  "B"  "C"  
# [5,] "A"  "D"  "C"  "A"  "B"  "D"  "A"  "C"  "D"  "C"