Question

我知道Rails有一些很好的日期和时间管理助手。是否有一个已经完成的项目由标准单元及其转换组成或包含干净的DSL？任何带有助手的项目都可以在两个系统的长度和重量基本单位之间进行转换。谢谢！

Answer 1

哇，这些比我预期的要多得多。以下是我认为的完整列表，按字母顺序排列，示例用法从文档中删除。我还注意到，如果我不能让它们在本地运行。

require 'alchemist'
Alchemist.setup
8.miles.to.meters
10.kilometers + 1.mile # 11.609344 kilometers

measurement

这个看起来已经过时了，最后一次提交是5年前的事，而且它似乎并没有在1.9.3上运行。
```
include Measurement::Length
Inch.new(12).to_centimeters # => #<Measurement::Length::Centimeter:0x173c2b4 @units=30.48>
```

Phys-Units

require "phys/units"
Q = Phys::Quantity
U = Phys::Unit

Q[1.23,'km'] + Q[4.56,'m']    #=> Phys::Quantity[1.23456,'km']
Q[123,'mile'] / Q[2,'hr']     #=> Phys::Quantity[61,'mile/hr']
Q[61,'miles/hr'].want('m/s')  #=> Phys::Quantity[27.26944,'m/s']
Q[1.0,'are'] == Q[10,'m']**2  #=> true

Quantity

请注意，这个说明它在README中没有生产就绪。

require 'quantity/all'
1.meter                                         #=> 1 meter
1.meter.to_feet                                 #=> 3.28083... foot
c = 299792458.meters / 1.second                 #=> 299792458 meter/second

newton = 1.meter * 1.kilogram / 1.second**2     #=> 1 meter*kilogram/second^2
newton.to_feet                                  #=> 3.28083989501312 foot*kilogram/second^2
newton.convert(:feet)                                   #=> 3.28083989501312 foot*kilogram/second^2
jerk_newton = newton / 1.second                         #=> 1 meter*kilogram/second^3
jerk_newton * 1.second == newton                        #=> true

SY

请参阅Boris Stitnickey's answer。

ruby-measurement

require 'ruby-measurement'

measurement = Measurement.parse('3 feet')  # => 3.0 ft.
measurement.convert_to(:yards)             # => 1.0 yd.
measurement.convert_to(:in)                # => 36.0 in.
measurement.convert_to(:inches)            # => 36.0 in.

measurement1 = Measurement.parse('3 feet') # => 3.0 ft.
measurement2 = Measurement.parse('6 inch') # => 6.0 in.
measurement1 + measurement2                # => 3.5 ft.

ruby-units

require 'ruby-units'

unit = Unit("mm")                # unit only (defaults to a scalar of 1)
unit = Unit("1 mm")              # create a simple unit
unit = Unit("1 kg*m^2/s^2")      # complex unit

unit1 =~ unit2                   # true if units are compatible
unit1.compatible?(unit2)         # true if units are compatible

unit1 = unit >> "ft"             # convert to 'feet'
unit3 = unit1 + unit2            # resulting object will have the units of unit1

unit1 === unit2                  # true if units and quantity are the same, even if 'equivalent' by <=>
unit.convert_to('ft')            # convert
(unit1 + unit2).convert_to('ft') # converts result to 'ft'

Units for Ruby

require 'units'

three_meters = 3.meters
two_meters = 2.m
one_inch = 1.inch

3.meters.to_inches # => 118.1103 inch
10.inches.to_mm    # => 254.0 millimeter

Unitwise

require 'unitwise/ext'

1.yard == (1.foot * 3)                       # => true

1.quart < 1.liter                            # => true

2.meter + 3.inch - 1.yard                    # => <Unitwise::Measurement 1.1618 meter>

1.convert_to('kg.m2/s2') == 1.joule          # => true

(20.kg * 9.8.convert_to('m/s2')).to_pound_force # => <Unitwise::Measurement 44.06255284754326 pound_force>

(300.horsepower * 60.second).to_calorie      # => <Unitwise::Measurement 3208077.8414151203 calorie>

Van/Unit

像另一张海报一样，我无法正常工作。但是，您可以查看Jörg W Mittag's answer的使用情况。

作为Unitwise的作者，可能很明显，这是我最喜欢的群体。不过，我鼓励你至少检查一下。

Answer 2

尝试很棒的Alchemist。

...

Answer 3

看看Tom Sawyer的Van/Unit

这是来自主页：

require 'van/units'
include Units

1.mile.to(feet)
1.acre.to(yd**2)
1.acre.to(sq_yd)
1.gallon.to(self.L)
1.lb.to(kg)
1.m.s.to(m.s)
1.sq_mi.to(km**2)
1.mile.to(km)
1.usd.to(twd)
1.bit/s + 8.bytes/s

Answer 4

尝试gem install sy

require 'sy'

( 5.g *                # a bullet of 5g
    500.m.s(-1) ** 2 / # flying at a speed of 500m/s has kJ energy:
2 ).in( :kJ )          #=> 0.625

require 'sy/imperial'    

1.mile.in :ft   #=> 5280.0
1.acre.in :yd²  #=> 4840.0
1.gallon.in :l  #=> 4.54609
1.lb.in :kg     #=> 0.45359237
1.mile².in :km² #=> 2.589988110336
SY::SPEED_OF_LIGHT.in "furlong.fortnight⁻¹" #=> 1802617499785.2544

Answer 5

我无法让Van /单位工作 - 所有报告都是：

/Library/Ruby/Gems/1.8/gems/vanunits-1.5.0/lib/van/units/base.rb:493:in `to'：操作不兼容的单位（类型错误）来自unitstest.rb：4

运行时

require 'rubygems' 
require 'van/units' 
include Van::Units puts
1.meter.to(feet)

我花了一个小时试图破解面包车/单位的来源失败。

它所基于的旧宝石开箱即用：

http://ruby-units.rubyforge.org/ruby-units/

Answer 6

vanunits似乎破碎了。我建议尝试

rubyunits（http://ruby-units.rubyforge.org/ruby-units/）

或

测量（https://github.com/collectiveidea/measurement）

用于转换Ruby中物理单位（千克，磅）的库？

6 个答案: