Package 'fourinarow'

Bot players for Four in a Row

Description

Computer players that select their next move based on various amounts of internal logic.

Usage

randomBot(game)

easyBot(game)

mediumBot(game)

hardBot(game)

Arguments

game	A 6x7 matrix object representing the current game board.

Value

Returns an integer between 1 and 7. Each bot only selects from the set of valid moves, so they won't select a column that is already full.

Functions

• randomBot(): Chooses moves randomly.

• easyBot(): Tries to make 4 in a row, but does not consider its opponents moves.

• mediumBot(): Selects a move based on simple internal logic. It tries to make 4 in a row and tries to block the opponent from winning, but does not consider possible downstream moves.

• hardBot(): Selects a move by looking three moves ahead (with downstream moves selected by internal logic similar to mediumBot).

Examples

play4inaRow(randomBot, easyBot)

play4inaRow(mediumBot, hardBot)

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All possible sets of 4 in a row

Description

Manually constructs a dataset containing all possible winning sets of four in a standard (6x7) game of Four in a Row.

Usage

getSetsof4()

Value

A matrix with 69 rows and 4 columns. Each row contains numeric indices for a potential winning set of four in a row. For example, sets[1,] represents the set of four vertical spaces starting in the top left corner.

Examples

getSetsof4()

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Human player

Description

Get moves as input from the command line, allowing users to play against a bot.

Usage

humanPlayer(game)

Arguments

game	A 6x7 matrix object representing the current game board.

Details

While possible, human vs. human games can be confusing because the game switches Xs and Os between turns (so that every player sees their own pieces as X).

Value

Prints the current game board and prompts the user to input a move, which must be an integer between 1 and 7 and a valid move in the current game.

Examples

play4inaRow(humanPlayer, randomBot)

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Switch X's and O's

Description

Convenience function called internally by play4inaRow that switches the player symbols, so that each player sees their own pieces as "X" and their opponents' as "O".

Usage

invertPieces(game)

Arguments

game	A 6x7 matrix object representing the current game board.

Value

Returns the game matrix with "X" and "O" symbols switched.

Examples

game <- matrix(sample(c('X','O','.'), 6*7, replace=TRUE), nrow = 6, ncol = 7)
game
invertPieces(game)

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Play a game of Four in a Row

Description

Play a game of Four in a Row

Usage

play4inaRow(playerOne, playerTwo, verbose = TRUE)

Arguments

playerOne	A function that takes the current board as input and returns the next move (1-7) for Player 1.
playerTwo	Same for Player 2. Note that both functions see their pieces as "X" and opponent's pieces as "O".
verbose	Logical value indicating whether or not to print the final board to the console (default is TRUE)

Details

The game is played on a $6 \times 7$ grid and players alternate placing markers in one of the $7$ columns. The piece will "fall" to the lowest unoccupied space in that column. The game ends when one player wins by getting four pieces in a row (horizontally, vertically, or diagonally).

Note that every player will see their markers as Xs when it is their turn.

Value

Returns 1 or 2 to indicate whether Player 1 or Player 2 was the winner. Returns 0 in the case of a tie.

Examples

play4inaRow(randomBot, randomBot)

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Simulate many games of Four in a Row

Description

This is a convenient way to test two bots against each other over a large number of games while ensuring that neither bot has an advantage from going first more often than the other.

Usage

testBots(playerOne, playerTwo, n = 100)

Arguments

playerOne	A function that takes the current board as input and returns the next move (1-7) for Player 1.
playerTwo	Same for Player 2. Note that both functions see their pieces as "X" and opponent's pieces as "O".
n	Numerical value of how many games to simulate. Must be an even number, so that both bots get the same number of games with the first move (default = 100).

Value

Returns a vector of counts for the number of ties, wins by playerOne, and wins by playerTwo.

Examples

testBots(easyBot, randomBot)

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