ruby中的数组元素配对

检查是否有效

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

例子

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公司

 GERMANY  Vs  NETHERLAND
 GERMANY  Vs  PARAGUAY
 GERMANY  Vs  ARGENTINA
 NETHERLAND  Vs  PARAGUAY
 NETHERLAND  Vs  ARGENTINA
 PARAGUAY  Vs  ARGENTINA

在Ruby1.8.7+中,您可以使用 Array#combination

teams = %w(A B C D)
matches = teams.combination(2).to_a

在1.8.6中,可以使用 Facets 要执行相同的操作:

require 'facets/array/combination'
# Same code as above.

在类匹配中,假设内部属性 red 和 blue

class Match
#...
  def ==(anOther)
    red == anOther.blue and anOther.red == blue
  end
#...
end

以及循环:

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

说明:

这个 include? 的功能 Array == 方法,所以您只需重写它并为它提供匹配所需的行为。