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small int clarification
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{
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"metadata": {
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"name": "",
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"signature": "sha256:161acdaa5124ca9e1082a3b0564e8792f64364ea91cd2cff096fdbbff37408ca"
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"signature": "sha256:e20426bb66111696c7ec4f8d754946061e129b3e332a6cc2fd00331b9540d8c5"
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},
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"nbformat": 3,
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"nbformat_minor": 0,
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"<a name='python_small_int'></a>\n",
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"## Python reuses objects for small integers - always use \"==\" for equality, \"is\" for identity\n",
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"\n",
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"This oddity occurs, because Python tends to stores small integers as the same object, but not so for larger ones! \n",
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"This oddity occurs, because Python keeps an array of small integer objects (i.e., integers between -5 and 256, [see the doc](https://docs.python.org/2/c-api/int.html#PyInt_FromLong)).\n",
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"\n",
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"\n",
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"(*I received a comment that this is in fact a CPython artefact and must not necessarily be true in all implementations of Python!*)\n",
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"\n",
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"So the take home message is: always use \"==\" for equality, \"is\" for identity!\n",
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@ -1,7 +1,7 @@
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{
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"metadata": {
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"name": "",
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"signature": "sha256:161acdaa5124ca9e1082a3b0564e8792f64364ea91cd2cff096fdbbff37408ca"
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"signature": "sha256:e20426bb66111696c7ec4f8d754946061e129b3e332a6cc2fd00331b9540d8c5"
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},
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"nbformat": 3,
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"nbformat_minor": 0,
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@ -212,7 +212,9 @@
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"<a name='python_small_int'></a>\n",
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"## Python reuses objects for small integers - always use \"==\" for equality, \"is\" for identity\n",
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"\n",
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"This oddity occurs, because Python tends to stores small integers as the same object, but not so for larger ones! \n",
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"This oddity occurs, because Python keeps an array of small integer objects (i.e., integers between -5 and 256, [see the doc](https://docs.python.org/2/c-api/int.html#PyInt_FromLong)).\n",
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"\n",
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"\n",
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"(*I received a comment that this is in fact a CPython artefact and must not necessarily be true in all implementations of Python!*)\n",
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"\n",
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"So the take home message is: always use \"==\" for equality, \"is\" for identity!\n",
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