head.logician_iterator: Return the first n results from an iterator

In dirkschumacher/logician: Logic Programming in R

Description

Return the first n results from an iterator

Usage

## S3 method for class 'logician_iterator'
head(x, n = 6, ...)

Arguments

x	an object
n	an length 1 integer >= 1. sometimes that can result in an infinite loop
...	unused dots

Value

For each solution a list of substitions.

Examples

database <- logician_database(
  connected(berlin, hamburg),
  connected(hamburg, chicago),
  connected(chicago, london),
  connected(aachen, berlin),
  connected(chicago, portland),
  connected(portland, munich),
  path(A, B) := connected(A, B),
  path(A, B) := connected(A, Z) && path(Z, B)
)
iter <- logician_query(database, path(berlin, X))
head(iter, 4) # get the first 4 results if they exists

dirkschumacher/logician documentation built on June 13, 2020, 5:11 p.m.