def Duration.as_str(arr)
s = ""
case arr.length
when 4
if arr[0] > 0
s << "#{arr[0]} days"
end
if arr[1] > 0
if s.length > 0
s << ', '
end
s << "#{arr[1]} hours"
end
if arr[2] > 0
if s.length > 0
s << ', '
end
s << "#{arr[2]} mins"
end
if arr[3] > 0
if s.length > 0
s << ', '
end
s << "#{arr[3]} secs"
end
when 3
if arr[0] > 0
s << "#{arr[0]} hours"
end
if arr[1] > 0
if s.length > 0
s << ', '
end
s << "#{arr[1]} mins"
end
if arr[2] > 0
if s.length > 0
s << ', '
end
s << "#{arr[2]} secs"
end
end
s
end