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1 | 1a305335 | officers | # Copyright (c) 2007, Robert Coup <robert.coup@onetrackmind.co.nz>
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2 | # All rights reserved.
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3 | #
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4 | # Redistribution and use in source and binary forms, with or without modification,
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5 | # are permitted provided that the following conditions are met:
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6 | #
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7 | # 1. Redistributions of source code must retain the above copyright notice,
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8 | # this list of conditions and the following disclaimer.
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9 | #
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10 | # 2. Redistributions in binary form must reproduce the above copyright
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11 | # notice, this list of conditions and the following disclaimer in the
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12 | # documentation and/or other materials provided with the distribution.
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13 | #
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14 | # 3. Neither the name of Distance nor the names of its contributors may be used
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15 | # to endorse or promote products derived from this software without
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16 | # specific prior written permission.
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17 | #
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18 | # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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19 | # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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20 | # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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21 | # DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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22 | # ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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23 | # (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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24 | # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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25 | # ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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26 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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27 | # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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28 | #
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29 | """
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30 | Distance and Area objects to allow for sensible and convienient calculation
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31 | and conversions.
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32 |
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33 | Authors: Robert Coup, Justin Bronn
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34 |
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35 | Inspired by GeoPy (http://exogen.case.edu/projects/geopy/)
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36 | and Geoff Biggs' PhD work on dimensioned units for robotics.
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37 | """
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38 | __all__ = ['A', 'Area', 'D', 'Distance'] |
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39 | from decimal import Decimal |
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40 | |||
41 | class MeasureBase(object): |
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42 | def default_units(self, kwargs): |
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43 | """
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44 | Return the unit value and the default units specified
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45 | from the given keyword arguments dictionary.
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46 | """
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47 | val = 0.0
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48 | for unit, value in kwargs.iteritems(): |
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49 | if not isinstance(value, float): value = float(value) |
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50 | if unit in self.UNITS: |
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51 | val += self.UNITS[unit] * value
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52 | default_unit = unit |
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53 | elif unit in self.ALIAS: |
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54 | u = self.ALIAS[unit]
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55 | val += self.UNITS[u] * value
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56 | default_unit = u |
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57 | else:
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58 | lower = unit.lower() |
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59 | if lower in self.UNITS: |
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60 | val += self.UNITS[lower] * value
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61 | default_unit = lower |
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62 | elif lower in self.LALIAS: |
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63 | u = self.LALIAS[lower]
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64 | val += self.UNITS[u] * value
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65 | default_unit = u |
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66 | else:
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67 | raise AttributeError('Unknown unit type: %s' % unit) |
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68 | return val, default_unit
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69 | |||
70 | @classmethod
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71 | def unit_attname(cls, unit_str): |
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72 | """
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73 | Retrieves the unit attribute name for the given unit string.
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74 | For example, if the given unit string is 'metre', 'm' would be returned.
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75 | An exception is raised if an attribute cannot be found.
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76 | """
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77 | lower = unit_str.lower() |
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78 | if unit_str in cls.UNITS: |
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79 | return unit_str
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80 | elif lower in cls.UNITS: |
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81 | return lower
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82 | elif lower in cls.LALIAS: |
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83 | return cls.LALIAS[lower]
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84 | else:
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85 | raise Exception('Could not find a unit keyword associated with "%s"' % unit_str) |
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86 | |||
87 | class Distance(MeasureBase): |
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88 | UNITS = { |
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89 | 'chain' : 20.1168, |
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90 | 'chain_benoit' : 20.116782, |
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91 | 'chain_sears' : 20.1167645, |
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92 | 'british_chain_benoit' : 20.1167824944, |
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93 | 'british_chain_sears' : 20.1167651216, |
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94 | 'british_chain_sears_truncated' : 20.116756, |
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95 | 'cm' : 0.01, |
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96 | 'british_ft' : 0.304799471539, |
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97 | 'british_yd' : 0.914398414616, |
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98 | 'clarke_ft' : 0.3047972654, |
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99 | 'clarke_link' : 0.201166195164, |
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100 | 'fathom' : 1.8288, |
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101 | 'ft': 0.3048, |
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102 | 'german_m' : 1.0000135965, |
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103 | 'gold_coast_ft' : 0.304799710181508, |
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104 | 'indian_yd' : 0.914398530744, |
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105 | 'inch' : 0.0254, |
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106 | 'km': 1000.0, |
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107 | 'link' : 0.201168, |
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108 | 'link_benoit' : 0.20116782, |
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109 | 'link_sears' : 0.20116765, |
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110 | 'm': 1.0, |
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111 | 'mi': 1609.344, |
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112 | 'mm' : 0.001, |
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113 | 'nm': 1852.0, |
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114 | 'nm_uk' : 1853.184, |
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115 | 'rod' : 5.0292, |
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116 | 'sears_yd' : 0.91439841, |
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117 | 'survey_ft' : 0.304800609601, |
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118 | 'um' : 0.000001, |
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119 | 'yd': 0.9144, |
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120 | } |
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121 | |||
122 | # Unit aliases for `UNIT` terms encountered in Spatial Reference WKT.
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123 | ALIAS = { |
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124 | 'centimeter' : 'cm', |
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125 | 'foot' : 'ft', |
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126 | 'inches' : 'inch', |
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127 | 'kilometer' : 'km', |
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128 | 'kilometre' : 'km', |
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129 | 'meter' : 'm', |
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130 | 'metre' : 'm', |
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131 | 'micrometer' : 'um', |
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132 | 'micrometre' : 'um', |
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133 | 'millimeter' : 'mm', |
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134 | 'millimetre' : 'mm', |
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135 | 'mile' : 'mi', |
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136 | 'yard' : 'yd', |
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137 | 'British chain (Benoit 1895 B)' : 'british_chain_benoit', |
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138 | 'British chain (Sears 1922)' : 'british_chain_sears', |
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139 | 'British chain (Sears 1922 truncated)' : 'british_chain_sears_truncated', |
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140 | 'British foot (Sears 1922)' : 'british_ft', |
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141 | 'British foot' : 'british_ft', |
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142 | 'British yard (Sears 1922)' : 'british_yd', |
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143 | 'British yard' : 'british_yd', |
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144 | "Clarke's Foot" : 'clarke_ft', |
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145 | "Clarke's link" : 'clarke_link', |
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146 | 'Chain (Benoit)' : 'chain_benoit', |
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147 | 'Chain (Sears)' : 'chain_sears', |
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148 | 'Foot (International)' : 'ft', |
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149 | 'German legal metre' : 'german_m', |
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150 | 'Gold Coast foot' : 'gold_coast_ft', |
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151 | 'Indian yard' : 'indian_yd', |
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152 | 'Link (Benoit)': 'link_benoit', |
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153 | 'Link (Sears)': 'link_sears', |
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154 | 'Nautical Mile' : 'nm', |
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155 | 'Nautical Mile (UK)' : 'nm_uk', |
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156 | 'US survey foot' : 'survey_ft', |
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157 | 'U.S. Foot' : 'survey_ft', |
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158 | 'Yard (Indian)' : 'indian_yd', |
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159 | 'Yard (Sears)' : 'sears_yd' |
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160 | } |
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161 | LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()]) |
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162 | |||
163 | def __init__(self, default_unit=None, **kwargs): |
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164 | # The base unit is in meters.
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165 | self.m, self._default_unit = self.default_units(kwargs) |
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166 | if default_unit and isinstance(default_unit, str): |
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167 | self._default_unit = default_unit
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168 | |||
169 | def __getattr__(self, name): |
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170 | if name in self.UNITS: |
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171 | return self.m / self.UNITS[name] |
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172 | else:
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173 | raise AttributeError('Unknown unit type: %s' % name) |
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174 | |||
175 | def __repr__(self): |
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176 | return 'Distance(%s=%s)' % (self._default_unit, getattr(self, self._default_unit)) |
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177 | |||
178 | def __str__(self): |
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179 | return '%s %s' % (getattr(self, self._default_unit), self._default_unit) |
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180 | |||
181 | def __cmp__(self, other): |
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182 | if isinstance(other, Distance): |
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183 | return cmp(self.m, other.m) |
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184 | else:
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185 | return NotImplemented |
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186 | |||
187 | def __add__(self, other): |
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188 | if isinstance(other, Distance): |
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189 | return Distance(default_unit=self._default_unit, m=(self.m + other.m)) |
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190 | else:
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191 | raise TypeError('Distance must be added with Distance') |
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192 | |||
193 | def __iadd__(self, other): |
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194 | if isinstance(other, Distance): |
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195 | self.m += other.m
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196 | return self |
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197 | else:
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198 | raise TypeError('Distance must be added with Distance') |
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199 | |||
200 | def __sub__(self, other): |
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201 | if isinstance(other, Distance): |
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202 | return Distance(default_unit=self._default_unit, m=(self.m - other.m)) |
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203 | else:
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204 | raise TypeError('Distance must be subtracted from Distance') |
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205 | |||
206 | def __isub__(self, other): |
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207 | if isinstance(other, Distance): |
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208 | self.m -= other.m
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209 | return self |
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210 | else:
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211 | raise TypeError('Distance must be subtracted from Distance') |
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212 | |||
213 | def __mul__(self, other): |
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214 | if isinstance(other, (int, float, long, Decimal)): |
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215 | return Distance(default_unit=self._default_unit, m=(self.m * float(other))) |
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216 | elif isinstance(other, Distance): |
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217 | return Area(default_unit='sq_' + self._default_unit, sq_m=(self.m * other.m)) |
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218 | else:
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219 | raise TypeError('Distance must be multiplied with number or Distance') |
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220 | |||
221 | def __imul__(self, other): |
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222 | if isinstance(other, (int, float, long, Decimal)): |
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223 | self.m *= float(other) |
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224 | return self |
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225 | else:
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226 | raise TypeError('Distance must be multiplied with number') |
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227 | |||
228 | def __rmul__(self, other): |
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229 | return self * other |
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230 | |||
231 | def __div__(self, other): |
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232 | if isinstance(other, (int, float, long, Decimal)): |
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233 | return Distance(default_unit=self._default_unit, m=(self.m / float(other))) |
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234 | else:
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235 | raise TypeError('Distance must be divided with number') |
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236 | |||
237 | def __idiv__(self, other): |
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238 | if isinstance(other, (int, float, long, Decimal)): |
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239 | self.m /= float(other) |
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240 | return self |
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241 | else:
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242 | raise TypeError('Distance must be divided with number') |
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243 | |||
244 | def __nonzero__(self): |
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245 | return bool(self.m) |
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246 | |||
247 | class Area(MeasureBase): |
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248 | # Getting the square units values and the alias dictionary.
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249 | UNITS = dict([('sq_%s' % k, v ** 2) for k, v in Distance.UNITS.items()]) |
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250 | ALIAS = dict([(k, 'sq_%s' % v) for k, v in Distance.ALIAS.items()]) |
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251 | LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()]) |
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252 | |||
253 | def __init__(self, default_unit=None, **kwargs): |
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254 | self.sq_m, self._default_unit = self.default_units(kwargs) |
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255 | if default_unit and isinstance(default_unit, str): |
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256 | self._default_unit = default_unit
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257 | |||
258 | def __getattr__(self, name): |
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259 | if name in self.UNITS: |
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260 | return self.sq_m / self.UNITS[name] |
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261 | else:
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262 | raise AttributeError('Unknown unit type: ' + name) |
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263 | |||
264 | def __repr__(self): |
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265 | return 'Area(%s=%s)' % (self._default_unit, getattr(self, self._default_unit)) |
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266 | |||
267 | def __str__(self): |
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268 | return '%s %s' % (getattr(self, self._default_unit), self._default_unit) |
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269 | |||
270 | def __cmp__(self, other): |
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271 | if isinstance(other, Area): |
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272 | return cmp(self.sq_m, other.sq_m) |
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273 | else:
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274 | return NotImplemented |
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275 | |||
276 | def __add__(self, other): |
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277 | if isinstance(other, Area): |
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278 | return Area(default_unit=self._default_unit, sq_m=(self.sq_m + other.sq_m)) |
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279 | else:
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280 | raise TypeError('Area must be added with Area') |
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281 | |||
282 | def __iadd__(self, other): |
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283 | if isinstance(other, Area): |
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284 | self.sq_m += other.sq_m
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285 | return self |
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286 | else:
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287 | raise TypeError('Area must be added with Area') |
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288 | |||
289 | def __sub__(self, other): |
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290 | if isinstance(other, Area): |
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291 | return Area(default_unit=self._default_unit, sq_m=(self.sq_m - other.sq_m)) |
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292 | else:
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293 | raise TypeError('Area must be subtracted from Area') |
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294 | |||
295 | def __isub__(self, other): |
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296 | if isinstance(other, Area): |
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297 | self.sq_m -= other.sq_m
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298 | return self |
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299 | else:
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300 | raise TypeError('Area must be subtracted from Area') |
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301 | |||
302 | def __mul__(self, other): |
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303 | if isinstance(other, (int, float, long, Decimal)): |
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304 | return Area(default_unit=self._default_unit, sq_m=(self.sq_m * float(other))) |
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305 | else:
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306 | raise TypeError('Area must be multiplied with number') |
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307 | |||
308 | def __imul__(self, other): |
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309 | if isinstance(other, (int, float, long, Decimal)): |
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310 | self.sq_m *= float(other) |
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311 | return self |
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312 | else:
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313 | raise TypeError('Area must be multiplied with number') |
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314 | |||
315 | def __rmul__(self, other): |
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316 | return self * other |
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317 | |||
318 | def __div__(self, other): |
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319 | if isinstance(other, (int, float, long, Decimal)): |
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320 | return Area(default_unit=self._default_unit, sq_m=(self.sq_m / float(other))) |
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321 | else:
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322 | raise TypeError('Area must be divided with number') |
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323 | |||
324 | def __idiv__(self, other): |
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325 | if isinstance(other, (int, float, long, Decimal)): |
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326 | self.sq_m /= float(other) |
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327 | return self |
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328 | else:
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329 | raise TypeError('Area must be divided with number') |
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330 | |||
331 | def __nonzero__(self): |
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332 | return bool(self.sq_m) |
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333 | |||
334 | # Shortcuts
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335 | D = Distance |
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336 | A = Area |