Let's say i have an array called teams.
I want to plan matches for every team with every other team.
This is almost what i want except that same matches are added twice:
teams.each do |red_team|
teams.each do |blue_team|
if red_team != blue_team
@planned_matches << Match.new(red_team, blue_team)
end
end
end
How to do that?
In Ruby 1.8.7+ you can use Array#combination:
teams = %w(A B C D)
matches = teams.combination(2).to_a
In 1.8.6, you can use Facets to do the same:
require 'facets/array/combination'
# Same code as above.
check if it works
for i in 0..teams.length-1
if i != teams.last
for j in (i+1)..teams.length-1
@planned_matches << Match.new(teams[i], teams[j])
end
end
end
EXAMPLE
teams = ['GERMANY', 'NETHERLAND', 'PARAGUAY', 'ARGENTINA']
for i in 0..teams.length-1
if i != teams.last
for j in (i+1)..teams.length-1
puts " #{teams[i]} Vs #{teams[j]}"
end
end
end
O/P
GERMANY Vs NETHERLAND
GERMANY Vs PARAGUAY
GERMANY Vs ARGENTINA
NETHERLAND Vs PARAGUAY
NETHERLAND Vs ARGENTINA
PARAGUAY Vs ARGENTINA
upto or ... or each_index. Also, for isn't idiosyncratic ruby.In your class Match, assuming internal attributes are red and blue
class Match
#...
def ==(anOther)
red == anOther.blue and anOther.red == blue
end
#...
end
and the loop :
teams.each do |red_team|
teams.each do |blue_team|
if red_team != blue_team
new_match = Match.new(red_team, blue_team)
planned_matches << new_match if !planned_matches.include?(new_match)
end
end
end
Explanation :
The include? function of Array uses the == methods, so you just have to override it and giving it the behaviour you want for your Matches.
