spatstat.utils (version 2.3-0)

verbalogic: Verbal Logic

Description

Perform the specified logical operation on the character vector x, recognising the special strings "TRUE" and "FALSE" and treating other strings as logical variables.

Usage

verbalogic(x, op = "and")

Arguments

x

Character vector.

op

Logical operation: one of the character strings "and", "or" or "not".

Value

A character string.

Details

This function performs simple logical operations on character strings that represent human-readable statements.

The character vector x may contain any strings: the special strings "TRUE" and "FALSE" are treated as the logical values TRUE and FALSE, while all other strings are treated as if they were logical variables.

If op="and", the result is a single string, logically equivalent to x[1] && x[2] && ... && x[n]. First, any entries of x equal to "TRUE" are removed. The result is "FALSE" if any of the entries of x is "FALSE"; otherwise it is equivalent to paste(x, collapse=" and ").

If op="or", the result is a single string, logically equivalent to x[1] || x[2] || ... || x[n]. First, any entries of x equal to "FALSE" are removed. The result is "TRUE" if any of the entries of x is "TRUE"; otherwise it is equivalent to paste(x, collapse=" or ").

If op="not", the result is a character vector y such that y[i] is the logical negation of x[i].

The code does not understand English grammar and cannot expand logical expressions.

Examples

# NOT RUN {
   x <- c("The sky is blue", "my name is not Einstein", "FALSE")
   verbalogic(x, "and")
   verbalogic(x, "or")
   verbalogic(x, "not")
# }