| 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, NewDict
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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 over strings')
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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 | log('-- list comprehension filtering')
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| 44 |
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| 45 | parts = ['a', None, 'b']
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| 46 | tmp = [s for s in parts if s is not None]
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| 47 | print(''.join(tmp))
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| 48 |
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| 49 | tmp2 = [s for s in tmp if s.startswith('-')]
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| 50 | print(''.join(tmp2))
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| 51 |
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| 52 |
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| 53 | def TestListCompParity():
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| 54 | # type: () -> None
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| 55 | """
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| 56 | Does it have all the same features as 'for' loops?
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| 57 |
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| 58 | - Integers
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| 59 | - xrange()
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| 60 | - Any type
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| 61 | - enumerate()
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| 62 |
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| 63 | - List
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| 64 | - unpacking of tuples
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| 65 | - Dict
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| 66 | - iterate directly over dict
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| 67 | - iteritem()
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| 68 | """
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| 69 | log('-- list comp xrange')
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| 70 | # BUG: it only works iterating over an List[T]
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| 71 | #numbers = [i+1 for i in xrange(3, 5)]
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| 72 | #PrintListStr(numbers)
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| 73 |
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| 74 | log('-- list comp enumerate')
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| 75 | mylist = [3, 4, 5]
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| 76 | # BUG: crashes on tuple expression
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| 77 | # enum = [i+item for i, item in enumerate(mylist)]
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| 78 |
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| 79 | log('-- list comp tuple unpacking')
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| 80 |
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| 81 | pairs = [('one', 1), ('two', 2)]
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| 82 |
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| 83 | # Note: listcomp_iter_var is at TOP level, but it could be SCOPED. It is
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| 84 | # also rooted at the top level.
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| 85 | first = [listcomp_iter_var for listcomp_iter_var, _ in pairs]
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| 86 |
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| 87 | for s2 in first:
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| 88 | log('first = %s', s2)
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| 89 |
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| 90 | log('-- list comp dict')
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| 91 | d = NewDict() # type: Dict[str, str]
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| 92 | d['k'] = 'v'
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| 93 | d['k2'] = 'v2'
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| 94 |
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| 95 | # BUG: generates TODO_DICT
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| 96 | #keys = [k for k in d]
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| 97 |
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| 98 | log('-- list comp iteritems')
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| 99 |
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| 100 | # BUG: generates TODO_DICT
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| 101 | #values = [v for k, v in iteritems(d)]
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| 102 |
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| 103 |
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| 104 | def TestDict():
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| 105 | # type: () -> None
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| 106 | log('--- Dict')
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| 107 | d = {} # type: Dict[str, int]
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| 108 | d['a'] = 99
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| 109 | d['c'] = 42
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| 110 | d['b'] = 0
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| 111 |
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| 112 | log('a = %d', d['a'])
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| 113 | log('b = %d', d['b'])
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| 114 | log('c = %d', d['c'])
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| 115 |
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| 116 | for k in d:
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| 117 | log("k = %s", k)
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| 118 |
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| 119 | for k, v in iteritems(d):
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| 120 | log("k = %s, v = %d", k, v)
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| 121 |
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| 122 |
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| 123 | CATS = ['big', 'small', 'hairless']
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| 124 |
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| 125 |
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| 126 | def TestForLoop():
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| 127 | # type: () -> None
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| 128 | log('--- iterate over bytes in string')
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| 129 | for ch in 'abc':
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| 130 | log('ch = %s', ch)
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| 131 |
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| 132 | log('--- iterate over items in list')
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| 133 | for item in ['xx', 'yy']:
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| 134 | log('item = %s', item)
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| 135 |
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| 136 | log('--- tuple unpacking')
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| 137 |
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| 138 | # Note: tuple_iter_1 and tuple_iter_2 are also top-level locals, and are
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| 139 | # rooted at the top level.
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| 140 | # They could be SCOPED.
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| 141 | list_of_tuples = [(5, 'five'), (6, 'six')]
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| 142 | for tuple_iter_1, tuple_iter_2 in list_of_tuples:
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| 143 | log("- [%d] %s", tuple_iter_1, tuple_iter_2)
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| 144 |
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| 145 | log('--- one arg xrange()')
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| 146 |
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| 147 | m = 2
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| 148 | n = 3
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| 149 |
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| 150 | for j in xrange(m * 2):
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| 151 | log("%d", j)
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| 152 |
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| 153 | log('--- two arg xrange()')
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| 154 |
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| 155 | # TODO: reuse index variable j
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| 156 | for k in xrange(m + 2, n + 5):
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| 157 | log("%d", k)
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| 158 |
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| 159 | log('--- three arg xrange()')
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| 160 |
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| 161 | # should iterate exactly once
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| 162 | for m in xrange(0, 5, 2):
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| 163 | log("%d", m)
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| 164 |
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| 165 | log('--- three arg reverse xrange()')
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| 166 |
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| 167 | # should iterate exactly once
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| 168 | for m in xrange(0, -1, -1):
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| 169 | log("reverse %d", m)
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| 170 |
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| 171 | log('--- enumerate()')
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| 172 |
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| 173 | for i, c in enumerate(CATS):
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| 174 | log('%d %s', i, c)
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| 175 |
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| 176 | for i, pair in enumerate(list_of_tuples):
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| 177 | index, s = pair
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| 178 | log('%d %d %s', i, index, s)
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| 179 |
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| 180 | # TODO: Note: might want to combine with enumerate? But we're not using
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| 181 | # that. We can specialize it for a list. ReverseListIter().
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| 182 | log('--- reversed() list')
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| 183 |
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| 184 | list_of_strings = ['spam', 'eggs']
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| 185 | for item in reversed(list_of_strings):
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| 186 | log("- %s", item)
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| 187 |
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| 188 | log('--- reversed() list with tuple unpacking')
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| 189 | for i, item in reversed(list_of_tuples):
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| 190 | log("- [%d] %s", i, item)
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| 191 |
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| 192 |
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| 193 | def run_tests():
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| 194 | # type: () -> None
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| 195 |
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| 196 | TestForLoop()
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| 197 |
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| 198 | TestListComp()
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| 199 | TestListCompParity()
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| 200 |
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| 201 | TestDict()
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| 202 |
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| 203 |
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| 204 | def run_benchmarks():
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| 205 | # type: () -> None
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| 206 | n = 500000
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| 207 |
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| 208 | result = 0
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| 209 |
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| 210 | i = 0
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| 211 | while i < n:
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| 212 | for j in xrange(3, 10):
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| 213 | result += j
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| 214 |
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| 215 | for j, c in enumerate(CATS):
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| 216 | result += j
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| 217 | result += len(c)
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| 218 |
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| 219 | i += 1
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| 220 | log('result = %d', result)
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| 221 | log('Ran %d iterations of xrange/enumerate', n)
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| 222 |
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| 223 |
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| 224 | if __name__ == '__main__':
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| 225 | if os.getenv('BENCHMARK'):
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| 226 | log('Benchmarking...')
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| 227 | run_benchmarks()
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| 228 | else:
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| 229 | run_tests()
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