1 | #!/usr/bin/env python2
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2 | """
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3 | loops.py: Common loops
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4 | """
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5 | from __future__ import print_function
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6 |
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7 | import os
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8 |
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9 | from mycpp import mylib
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10 | from mycpp.mylib import log, iteritems
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11 |
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12 | from typing import Dict
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13 |
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14 |
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15 | def TestListComp():
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16 | # type: () -> None
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17 | log('--- list comprehension')
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18 |
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19 | x = [1, 2, 3, 4]
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20 |
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21 | y = [i * 5 for i in x[1:]]
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22 |
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23 | log("len = %d", len(y))
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24 | log("y[0] = %d", y[0])
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25 | log("y[-1] = %d", y[-1])
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26 |
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27 | log('--- list comprehension changing type')
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28 |
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29 | z = ['[%d]' % i for i in x[1:-1]]
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30 |
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31 | # I think this rewrite might be necessary?
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32 | #tmp1 = x[1:-1]
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33 | #z = ['[%d]' % i for i in tmp1]
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34 |
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35 | if mylib.PYTHON:
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36 | #log("z = %s", z)
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37 | pass
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38 |
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39 | log("len = %d", len(z))
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40 | log("z[0] = %s", z[0])
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41 | log("z[-1] = %s", z[-1])
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42 |
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43 | pairs = [('one', 1), ('two', 2)]
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44 | first = [s for s, _ in pairs]
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45 | for s2 in first:
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46 | log('first = %s', s2)
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47 |
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48 | parts = ['a', None, 'b']
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49 | tmp = [s for s in parts if s is not None]
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50 | print(''.join(tmp))
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51 |
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52 | tmp2 = [s for s in tmp if s.startswith('-')]
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53 | print(''.join(tmp2))
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54 |
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55 |
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56 | def TestDict():
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57 | # type: () -> None
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58 | log('--- Dict')
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59 | d = {} # type: Dict[str, int]
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60 | d['a'] = 99
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61 | d['c'] = 42
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62 | d['b'] = 0
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63 |
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64 | log('a = %d', d['a'])
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65 | log('b = %d', d['b'])
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66 | log('c = %d', d['c'])
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67 |
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68 | for k in d:
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69 | log("k = %s", k)
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70 |
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71 | for k, v in iteritems(d):
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72 | log("k = %s, v = %d", k, v)
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73 |
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74 |
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75 | CATS = ['big', 'small', 'hairless']
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76 |
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77 | #EMPTY_DICT = {} # type: Dict[int, int]
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78 |
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79 |
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80 | def run_tests():
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81 | # type: () -> None
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82 |
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83 | log('--- iterate over bytes in string')
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84 | for ch in 'abc':
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85 | log('ch = %s', ch)
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86 |
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87 | log('--- iterate over items in list')
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88 | for item in ['xx', 'yy']:
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89 | log('item = %s', item)
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90 |
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91 | # TODO: iterate over items in dict
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92 | # DictIter gives pairs? Just do .Key() and .Value()? Hm that makes sense.
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93 |
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94 | log('--- tuple unpacking')
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95 |
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96 | list_of_tuples = [(5, 'five'), (6, 'six')]
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97 | for i, item in list_of_tuples:
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98 | log("- [%d] %s", i, item)
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99 |
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100 | log('--- one arg xrange()')
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101 |
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102 | m = 2
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103 | n = 3
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104 |
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105 | for j in xrange(m * 2):
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106 | log("%d", j)
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107 |
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108 | log('--- two arg xrange()')
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109 |
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110 | # TODO: reuse index variable j
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111 | for k in xrange(m + 2, n + 5):
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112 | log("%d", k)
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113 |
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114 | log('--- three arg xrange()')
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115 |
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116 | # should iterate exactly once
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117 | for m in xrange(0, 5, 2):
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118 | log("%d", m)
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119 |
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120 | log('--- three arg reverse xrange()')
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121 |
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122 | # should iterate exactly once
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123 | for m in xrange(0, -1, -1):
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124 | log("reverse %d", m)
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125 |
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126 | log('--- enumerate()')
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127 |
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128 | for i, c in enumerate(CATS):
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129 | log('%d %s', i, c)
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130 |
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131 | for i, pair in enumerate(list_of_tuples):
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132 | index, s = pair
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133 | log('%d %d %s', i, index, s)
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134 |
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135 | # TODO: Note: might want to combine with enumerate? But we're not using
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136 | # that. We can specialize it for a list. ReverseListIter().
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137 | log('--- reversed() list')
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138 |
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139 | list_of_strings = ['spam', 'eggs']
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140 | for item in reversed(list_of_strings):
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141 | log("- %s", item)
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142 |
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143 | log('--- reversed() list with tuple unpacking')
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144 | for i, item in reversed(list_of_tuples):
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145 | log("- [%d] %s", i, item)
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146 |
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147 | TestListComp()
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148 |
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149 | TestDict()
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150 |
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151 |
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152 | def run_benchmarks():
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153 | # type: () -> None
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154 | n = 500000
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155 |
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156 | result = 0
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157 |
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158 | i = 0
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159 | while i < n:
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160 | for j in xrange(3, 10):
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161 | result += j
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162 |
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163 | for j, c in enumerate(CATS):
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164 | result += j
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165 | result += len(c)
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166 |
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167 | i += 1
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168 | log('result = %d', result)
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169 | log('Ran %d iterations of xrange/enumerate', n)
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170 |
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171 |
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172 | if __name__ == '__main__':
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173 | if os.getenv('BENCHMARK'):
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174 | log('Benchmarking...')
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175 | run_benchmarks()
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176 | else:
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177 | run_tests()
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