67 lines
2.1 KiB
R
67 lines
2.1 KiB
R
truth_table <- function(x) {
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vars <- unique(unlist(strsplit(x, "[^a-zA-Z]+")))
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vars <- vars[vars != ""]
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perm <- expand.grid(rep(list(c(FALSE, TRUE)), length(vars)))
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names(perm) <- vars
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perm[ , x] <- with(perm, eval(parse(text = x)))
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perm
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}
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"%^%" <- xor # define unary xor operator
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truth_table("!A") # not
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## A !A
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## 1 FALSE TRUE
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## 2 TRUE FALSE
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truth_table("A | B") # or
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## A B A | B
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## 1 FALSE FALSE FALSE
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## 2 TRUE FALSE TRUE
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## 3 FALSE TRUE TRUE
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## 4 TRUE TRUE TRUE
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truth_table("A & B") # and
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## A B A & B
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## 1 FALSE FALSE FALSE
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## 2 TRUE FALSE FALSE
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## 3 FALSE TRUE FALSE
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## 4 TRUE TRUE TRUE
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truth_table("A %^% B") # xor
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## A B A %^% B
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## 1 FALSE FALSE FALSE
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## 2 TRUE FALSE TRUE
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## 3 FALSE TRUE TRUE
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## 4 TRUE TRUE FALSE
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truth_table("S | (T %^% U)") # 3 variables with brackets
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## S T U S | (T %^% U)
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## 1 FALSE FALSE FALSE FALSE
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## 2 TRUE FALSE FALSE TRUE
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## 3 FALSE TRUE FALSE TRUE
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## 4 TRUE TRUE FALSE TRUE
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## 5 FALSE FALSE TRUE TRUE
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## 6 TRUE FALSE TRUE TRUE
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## 7 FALSE TRUE TRUE FALSE
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## 8 TRUE TRUE TRUE TRUE
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truth_table("A %^% (B %^% (C %^% D))") # 4 variables with nested brackets
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## A B C D A %^% (B %^% (C %^% D))
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## 1 FALSE FALSE FALSE FALSE FALSE
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## 2 TRUE FALSE FALSE FALSE TRUE
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## 3 FALSE TRUE FALSE FALSE TRUE
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## 4 TRUE TRUE FALSE FALSE FALSE
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## 5 FALSE FALSE TRUE FALSE TRUE
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## 6 TRUE FALSE TRUE FALSE FALSE
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## 7 FALSE TRUE TRUE FALSE FALSE
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## 8 TRUE TRUE TRUE FALSE TRUE
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## 9 FALSE FALSE FALSE TRUE TRUE
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## 10 TRUE FALSE FALSE TRUE FALSE
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## 11 FALSE TRUE FALSE TRUE FALSE
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## 12 TRUE TRUE FALSE TRUE TRUE
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## 13 FALSE FALSE TRUE TRUE FALSE
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## 14 TRUE FALSE TRUE TRUE TRUE
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## 15 FALSE TRUE TRUE TRUE TRUE
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## 16 TRUE TRUE TRUE TRUE FALSE
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