我在Ruby中有很多时间范围：
period = Time.parse('8:00am')..Time.parse('8:00pm')
incidents = [
Time.parse('7:00am')..Time.parse('9:00am'),
Time.parse('1:00pm')..Time.parse('3:00pm'),
Time.parse('1:30pm')..Time.parse('3:30pm'),
Time.parse('7:00pm')..Time.parse('9:00pm'),
]
我试图在这段时间内获得一系列事件空闲块。对于上述内容，应该是：
[
Time.parse('9:00am')..Time.parse('1:00pm')
Time.parse('3:30pm')..Time.parse('7:00pm')
]
根据上述情况，事件可能会重叠或延伸到期间之外。范围或类似的任何操作是否会使这种计算变得更简单？
答案 0 :(得分：3)
使用此range operator gem，此脚本（几乎）将返回您想要的内容。
以period开头，并逐个减去每个incident。
由于从另一个范围中减去一个范围可能会产生两个范围，因此该脚本实际上以[period]开头，并在迭代之间保留一系列免费事件范围：
require 'range_operators'
incident_free = incidents.inject([period]) do |free_ranges, incident|
free_ranges.flat_map do |free_range|
free_range - incident
end
end
p incident_free
#=> [2016-12-22 09:00:01 +0100..2016-12-22 12:59:59 +0100, 2016-12-22 15:30:01 +0100..2016-12-22 18:59:59 +0100]
它抱怨Time#succ已经过时了。您可以添加
class Time
def succ
self+1
end
end
删除弃用警告，或使用Gemfile：
gem 'range_operators', :git => 'https://github.com/monocle/range_operators.git'
安装较新版本的gem，并修复Time。
该脚本的分辨率为1秒，第一个范围从09:00:01开始，因为在09:00:00之前发生了一次事件。
答案 1 :(得分：2)
让full_range为范围，ranges为范围数组，分别代表提问者称为period和incidents的内容。我假设所有范围中包含的元素都可以是任何对象，前提是它们可以与适用的类别进行比较。方法<=>以及模块Comparable已include d。
<强>代码
def uncovered_ranges(full_range, ranges)
ucrs = [full_range]
ranges.each do |r|
ucrs = ucrs.flat_map do |ucr|
if ucr.first >= r.last || ucr.last <= r.first
ucr
elsif r.first <= ucr.first && r.last >= ucr.last
nil
elsif r.first <= ucr.first && r.last < ucr.last
r.last..ucr.last
elsif r.first > ucr.first && r.last >= ucr.last
ucr.first..r.first
else
[ucr.first..r.first, r.last..ucr.last]
end
end.compact
end
ucrs
end
<强>实施例
full_range = 1..20
ranges = [3..4, 6..8, 10..12, 8..14, 16..17, 20..20]
uncovered_ranges(full_range, ranges)
#=> [1..3, 4..6, 14..16, 17..20]
require 'time'
full_range = Time.parse('8:00am')..Time.parse('8:00pm')
#=> 2016-12-22 08:00:00 -0800..2016-12-22 20:00:00 -0800
ranges = [
Time.parse('7:00am')..Time.parse('9:00am'),
Time.parse('1:00pm')..Time.parse('3:00pm'),
Time.parse('1:30pm')..Time.parse('3:30pm'),
Time.parse('7:00pm')..Time.parse('9:00pm'),
]
#=> [2016-12-22 07:00:00 -0800..2016-12-22 09:00:00 -0800,
# 2016-12-22 13:00:00 -0800..2016-12-22 15:00:00 -0800,
# 2016-12-22 13:30:00 -0800..2016-12-22 15:30:00 -0800,
# 2016-12-22 19:00:00 -0800..2016-12-22 21:00:00 -0800]
uncovered_ranges(full_range, ranges)
#=> [2016-12-22 09:00:00 -0800..2016-12-22 13:00:00 -0800,
# 2016-12-22 15:30:00 -0800..2016-12-22 19:00:00 -0800]
<强>解释
对我来说，解释发生了什么的最简单也是最简单的方法是插入一些puts语句并运行上面第一个例子的代码。
def uncovered_ranges(full_range, ranges)
ucrs = [full_range]
puts "ucrs initially=#{ucrs}"
ranges.each do |r|
puts "\ncovering range r=#{r}"
ucrs = ucrs.flat_map do |ucr|
puts " range uncovered so far ucr=#{ucr}"
if ucr.first >= r.last || ucr.last <= r.first
puts " in if #1, returning #{ucr}"
ucr
elsif r.first <= ucr.first && r.last >= ucr.last
puts " in if #2, returning nil"
nil
elsif r.first <= ucr.first && r.last < ucr.last
puts " in if #3, returning #{r.last..ucr.last}"
r.last..ucr.last
elsif r.first > ucr.first && r.last >= ucr.last
puts " in if #4, returning #{ucr.first..r.first}"
ucr.first..r.first
else
puts " in else, returning #{[ucr.first..r.first, r.last..ucr.last]}"
[ucr.first..r.first, r.last..ucr.last]
end
end.tap { |u| puts "ucrs after processing range #{r}=#{u}" }.
compact.
tap { |u| puts "ucrs after compact=#{u}" }
end
ucrs
end
uncovered_ranges 1..20, [3..4, 6..8, 10..12, 8..14, 16..17, 20..20]
打印以下内容。
ucrs initially=[1..20]
covering range r=3..4
range uncovered so far ucr=1..20
in else, returning [1..3, 4..20]
ucrs after processing range 3..4=[1..3, 4..20]
ucrs after compact=[1..3, 4..20]
covering range r=6..8
range uncovered so far ucr=1..3
in if #1, returning 1..3
range uncovered so far ucr=4..20
in else, returning [4..6, 8..20]
ucrs after processing range 6..8=[1..3, 4..6, 8..20]
ucrs after compact=[1..3, 4..6, 8..20]
covering range r=10..12
range uncovered so far ucr=1..3
in if #1, returning 1..3
range uncovered so far ucr=4..6
in if #1, returning 4..6
range uncovered so far ucr=8..20
in else, returning [8..10, 12..20]
ucrs after processing range 10..12=[1..3, 4..6, 8..10, 12..20]
ucrs after compact=[1..3, 4..6, 8..10, 12..20]
covering range r=8..14
range uncovered so far ucr=1..3
in if #1, returning 1..3
range uncovered so far ucr=4..6
in if #1, returning 4..6
range uncovered so far ucr=8..10
in if #2, returning nil
range uncovered so far ucr=12..20
in if #3, returning 14..20
ucrs after processing range 8..14=[1..3, 4..6, nil, 14..20]
ucrs after compact=[1..3, 4..6, 14..20]
covering range r=16..17
range uncovered so far ucr=1..3
in if #1, returning 1..3
range uncovered so far ucr=4..6
in if #1, returning 4..6
range uncovered so far ucr=14..20
in else, returning [14..16, 17..20]
ucrs after processing range 16..17=[1..3, 4..6, 14..16, 17..20]
ucrs after compact=[1..3, 4..6, 14..16, 17..20]
covering range r=20..20
range uncovered so far ucr=1..3
in if #1, returning 1..3
range uncovered so far ucr=4..6
in if #1, returning 4..6
range uncovered so far ucr=14..16
in if #1, returning 14..16
range uncovered so far ucr=17..20
in if #1, returning 17..20
ucrs after processing range 20..20=[1..3, 4..6, 14..16, 17..20]
ucrs after compact=[1..3, 4..6, 14..16, 17..20]
#=> [1..3, 4..6, 14..16, 17..20]