Question

I would like to sort my games by game_date, but sometimes the game_date may be null, and I will get an exception: undefined method `to_datetime’ for nil:NilClass

@games = @teams.reduce([]) { |memo, team| memo + team.games }.sort_by(&:game_date)

Any good way of doing this?

Answer 1

If you just want to drop entries without date, simplest solution –

ar.select(&:date).sort_by(&:date)

adding nils at the end can be done with

ar.select(&:date).sort_by(&:date) + ar.reject(&:date)

If you happen to know the range of possible dates, you can be fine with something like

ar.sort_by{|e| e.date || Date.new(9999)}

BTW, reduce in your statement can be changed to (IMHO) more clear

@games = @teams.map(&:games).flatten