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