Simple Array assignments

Question

I am just trying to make a function that fills an array with objects, but something is wrong:

row1 = []

class Tile
    def initialize(type)
        @type = type
    end
end

def FillRow1

    [1..10].each {
        random = rand(1..3)
        if random == 1 row1.(Tile.new("land") end 
        else if random == 2 row1.(Tile.new("Water") end
        else ifrandom == 3 row1.(Tile.new("empty") end
    }
    row1
end

Need4Steed · Accepted Answer · 2012-10-05T11:56:28.207

4

Your syntax is wrong

    [1..10].each {
        random = rand(1..3)
        if random == 1 then row1.push(Tile.new("land")) end 
        else if random == 2 then row1.push(Tile.new("Water")) end
        else ifrandom == 3 then row1.push(Tile.new("empty") end
    }

This would work.

But a cleaner solution may be:

types = ["Land","Water","Empty"]
10.times{ row1 << Tile.new(types[rand(0..2)]) }

edited Oct 05 '12 at 11:56

answered Oct 05 '12 at 11:42

Need4Steed

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so "<<" adds the object to the array? And I can use rand directly on arrays? – Борис Цейтлин Oct 05 '12 at 11:59
Yes, `<<` is an overloaded operator, basically a syntax sugar for `push`. And we're not using rand on an array, instead, we only used the result, rand(x..y) returns a number, which we used as the index to fetch the corresponding item of the array `types`. – Need4Steed Oct 05 '12 at 12:12

score 0 · Answer 2 · answered Oct 05 '12 at 11:53

0

Your second else if is wrong, there must be a space between random and the if.

answered Oct 05 '12 at 11:53

nurettin · Answer 3 · 2012-10-05T11:59:55.343

0

a= ["land", "water", "empty"]
data= (1..10).map{ a[rand(3)] }
p data

edited Oct 05 '12 at 11:59

answered Oct 05 '12 at 11:54

nurettin

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score 0 · Answer 4 · answered Oct 05 '12 at 12:13

0

A one-line option:

10.times.map{ Tile.new(["land","water","empty"][rand(3)]) }

answered Oct 05 '12 at 12:13

Mark Thomas

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score 0 · Answer 5 · answered Oct 05 '12 at 12:26

Recent versions of Ruby (>= 1.9.3) come with method #sample. It is part of Array. You can use it to get random element(s) from array without even knowing how big array even is.

class Tile
    TILE_TYPES = %w(land water empty)

    def initialize(type)
        @type = type
    end

    def to_s
        "Tile of type: #{@type}"
    end
end

# Generate 10 tiles
rows = (1..10).map do 
    Tile.new Tile::TILE_TYPES.sample
end

puts rows
#=> Tile of type: empty
#   Tile of type: land
#   ...

# If you want to pick more then 1 random element you can also do
puts Tile::TILE_TYPES.sample(3)

score 0 · Answer 6 · edited Oct 05 '12 at 20:37

0

class Tile
  def initialize(type)
    @type = type
  end
end

types = %w(land water empty)

row = Array.new(10){ Tile.new(types.sample) }

edited Oct 05 '12 at 20:37

Emil

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answered Oct 05 '12 at 18:16

steenslag

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@Emil 2 spaces indentation is [standard in ruby](http://stackoverflow.com/questions/2678817/2-spaces-or-1-tab-whats-the-standard-for-indentation-in-the-rails-community). – steenslag Oct 05 '12 at 19:13

Simple Array assignments

6 Answers6