Contenu connexe Plus de Kenta Murata (13) 5. インストール方法
mrkn-macbook:~ root# gem install -r measure
Bulk updating Gem source index for: http://gems.rubyforge.org
Successfully installed measure-0.1.0
1 gem installed
Installing ri documentation for measure-0.1.0...
Installing RDoc documentation for measure-0.1.0...
mrkn-macbook:~ root#
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6. 使い方
mrkn-macbook:~ root# irb
irb(main):001:0> require 'measure'
irb(main):002:0> Measure.define_unit :m, :length
irb(main):003:0> Measure.define_unit :cm, :length
irb(main):004:0> Measure(1, :m)
=> #<Measure:0x57d8c @unit=:m, @value=1>
irb(main):005:0> Measure(1, :cm).to_s
=> "1 [cm]"
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7. 単位変換
irb(main):006:0> Measure.define_conversion :m, :cm => 100
irb(main):007:0> (Measure(1, :m) + Measure(1, :cm)).to_s
=> "1.01 [m]"
irb(main):008:0> Measure.define_unit :in, :length
irb(main):009:0> Measure.define_conversion :in, :cm => 2.54
irb(main):010:0> Measure.define_unit :mm, :length
irb(main):011:0> Measure.define_conversion :m, :mm => 1000
irb(main):012:0> (Measure(210, :mm) - 2*Measure(1, :in)).to_s
=> "159.2 [mm]"
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9. マルチホップ変換
[in] 2.54倍 [cm]
100分の1
2.54分の1
100倍
[m]
1000倍
1000倍
[mm]
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10. マルチホップ変換
[in] 2.54倍 [cm]
100分の1
2.54分の1
100倍
[m]
1000倍
連結な単位間での 1000倍
相互変換の経路を [mm]
幅優先探索で発見
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12. 定義済み単位
measure/length を require すると次の単
位が定義され相互変換可能な状態になる
m, meter in, inch pt, point, dp, didot_point
cm, centi_meter ft, feet bp, big_point
mm, milli_meter yd, yard pc, pica
km, kilo_meter
um, micro_meter
nm, nano_meter
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13. 未対応な機能
多次元単位
たとえば 1 [kg m / s2] など
簡易記法なら 1.kg.m.s(‒2) かな？
スケーリング以外の単位変換
[ C] = 5 ([ F] ‒ 32) / 9 など
開発版では対応済み
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14. Proc による単位変換
irb(main):015:0> Measure.define_unit :deg_c, :temperature
irb(main):016:0> Measure.define_unit :deg_f, :temperature
irb(main):017:0> Measure.define_conversion :deg_c, :deg_f => lambda
{|x| 9.0*x/5.0 + 32 }
irb(main):018:0> Measure.define_conversion :deg_f, :deg_c => lambda
{|x| 5.0*(x - 32)/9.0 }
irb(main):019:0> Measure.form { -40.deg_c.as_deg_f }.to_s
=> "-40.0 [deg_f]"
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