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https://github.com/rasbt/python_reference.git
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is int
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rasbt
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"metadata": {
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"metadata": {
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"name": "",
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"name": "",
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"signature": "sha256:57df5708c2fce146df742136edf2eebb38c32146ab9e612bfd303a086b5bf7d9"
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"signature": "sha256:5f459d4c7e1521c71838da53736d2fbffd43b39d57d8b653cde1ec9333346574"
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"nbformat_minor": 0,
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@ -18,6 +18,17 @@
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"[Link to this IPython Notebook on GitHub](https://github.com/rasbt/python_reference/blob/master/benchmarks/timeit_tests.ipynb)"
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"[Link to this IPython Notebook on GitHub](https://github.com/rasbt/python_reference/blob/master/benchmarks/timeit_tests.ipynb)"
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]
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]
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},
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<hr>\n",
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"I am really looking forward to your comments and suggestions to improve and extend this collection! Just send me a quick note \n",
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"via Twitter: [@rasbt](https://twitter.com/rasbt) \n",
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"or Email: [bluewoodtree@gmail.com](mailto:bluewoodtree@gmail.com)\n",
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"<hr>"
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]
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},
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{
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"cell_type": "markdown",
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"cell_type": "markdown",
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"metadata": {},
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"metadata": {},
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@ -37,6 +48,8 @@
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" - [String reversing: [::-1] vs. `''.join(reversed())`](#str_reverse)\n",
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" - [String reversing: [::-1] vs. `''.join(reversed())`](#str_reverse)\n",
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" - [String concatenation: `+=` vs. `''.join()`](#string_concat)\n",
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" - [String concatenation: `+=` vs. `''.join()`](#string_concat)\n",
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" - [Assembling strings](#string_assembly) \n",
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" - [Assembling strings](#string_assembly) \n",
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" - [Testing if a string is an integer](#is_integer)\n",
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" - [Testing if a string is a number](#is_number)\n",
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"- [List operations](#list_operations)\n",
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"- [List operations](#list_operations)\n",
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" - [List reversing: [::-1] vs. reverse() vs. reversed()](#list_reverse)\n",
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" - [List reversing: [::-1] vs. reverse() vs. reversed()](#list_reverse)\n",
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" - [Creating lists using conditional statements](#create_cond_list)\n",
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" - [Creating lists using conditional statements](#create_cond_list)\n",
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@ -229,6 +242,8 @@
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"cell_type": "markdown",
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"cell_type": "markdown",
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"metadata": {},
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"metadata": {},
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"source": [
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"source": [
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"<br>\n",
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"<br>\n",
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"<a name='string_assembly'></a>\n",
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"<a name='string_assembly'></a>\n",
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"## Assembling strings\n",
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"## Assembling strings\n",
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"\n",
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"\n",
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"cell_type": "markdown",
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"cell_type": "markdown",
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"metadata": {},
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"metadata": {},
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"source": [
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"source": [
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"<br>\n",
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"<br>\n",
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"<a name='is_integer'></a>\n",
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"## Testing if a string is an integer"
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]
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},
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{
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"cell_type": "code",
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"collapsed": false,
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"input": [
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"import timeit\n",
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"\n",
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"def string_is_int(a_str):\n",
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" try:\n",
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" int(a_str)\n",
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" return True\n",
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" except ValueError:\n",
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" return False\n",
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"\n",
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"an_int = '123'\n",
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"no_int = '123abc'\n",
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"\n",
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"%timeit string_is_int(an_int)\n",
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"%timeit string_is_int(no_int)\n",
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"%timeit an_int.isdigit()\n",
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"%timeit no_int.isdigit()\n",
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"\n",
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"#\n",
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"# Python 3.4.0\n",
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"# MacOS X 10.9.2\n",
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"# 2.5 GHz Intel Core i5\n",
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"# 4 GB 1600 Mhz DDR3\n",
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"#"
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],
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"language": "python",
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"metadata": {},
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"outputs": [
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{
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"output_type": "stream",
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"stream": "stdout",
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"text": [
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"1000000 loops, best of 3: 401 ns per loop\n",
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"100000 loops, best of 3: 3.04 \u00b5s per loop"
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]
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},
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{
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"output_type": "stream",
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"stream": "stdout",
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"text": [
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"\n",
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"10000000 loops, best of 3: 92.1 ns per loop"
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]
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},
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{
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"output_type": "stream",
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"stream": "stdout",
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"text": [
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"\n",
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"10000000 loops, best of 3: 96.3 ns per loop"
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]
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},
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{
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"output_type": "stream",
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"stream": "stdout",
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"text": [
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"\n"
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]
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}
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],
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"prompt_number": 5
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<br>\n",
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"<br>\n",
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"<a name='is_number'></a>\n",
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"## Testing if a string is a number"
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]
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},
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{
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"cell_type": "code",
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"collapsed": false,
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"input": [
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"import timeit\n",
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"\n",
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"def string_is_number(a_str):\n",
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" try:\n",
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" float(a_str)\n",
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" return True\n",
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" except ValueError:\n",
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" return False\n",
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" \n",
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"a_float = '1.234'\n",
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"no_float = '123abc'\n",
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"\n",
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"a_float.replace('.','',1).isdigit()\n",
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"no_float.replace('.','',1).isdigit()\n",
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"\n",
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"%timeit string_is_number(an_int)\n",
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"%timeit string_is_number(no_int)\n",
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"%timeit a_float.replace('.','',1).isdigit()\n",
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"%timeit no_float.replace('.','',1).isdigit()\n",
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"\n",
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"#\n",
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"# Python 3.4.0\n",
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"# MacOS X 10.9.2\n",
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"# 2.5 GHz Intel Core i5\n",
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"# 4 GB 1600 Mhz DDR3\n",
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"#"
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],
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"language": "python",
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"metadata": {},
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"outputs": [
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{
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"output_type": "stream",
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"stream": "stdout",
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"text": [
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"1000000 loops, best of 3: 400 ns per loop\n",
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"1000000 loops, best of 3: 1.15 \u00b5s per loop"
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]
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},
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{
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"output_type": "stream",
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"stream": "stdout",
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"text": [
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"\n",
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"1000000 loops, best of 3: 452 ns per loop"
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]
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},
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{
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"output_type": "stream",
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"stream": "stdout",
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"text": [
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"\n",
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"1000000 loops, best of 3: 394 ns per loop"
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]
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},
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{
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"output_type": "stream",
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"stream": "stdout",
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"text": [
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"\n"
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]
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}
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],
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"prompt_number": 6
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<br>\n",
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"<br>\n",
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"<a name='list_operations'></a>\n",
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"<a name='list_operations'></a>\n",
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"# List operations"
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"# List operations"
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]
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]
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"### Conclusion\n",
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"### Conclusion\n",
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"Interestingly, the `try-except` loop pays off if we have more elements (here: 1000 integers instead of 100) as dictionary keys to check. Also, it doesn't matter much whether the elements exist or do not exist in the dictionary, yet."
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"Interestingly, the `try-except` loop pays off if we have more elements (here: 1000 integers instead of 100) as dictionary keys to check. Also, it doesn't matter much whether the elements exist or do not exist in the dictionary, yet."
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]
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]
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},
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{
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"cell_type": "code",
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"collapsed": false,
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"input": [],
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"language": "python",
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"metadata": {},
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"outputs": []
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}
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}
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],
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],
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"metadata": {}
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"metadata": {}
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