mirror of
https://github.com/rasbt/python_reference.git
synced 2025-01-18 15:27:09 +00:00
adding dict elements
This commit is contained in:
rasbt
parent
e342e59c66
commit
1fb82d58f3
|
|
@ -1,7 +1,7 @@
|
|||
{
|
||||
"metadata": {
|
||||
"name": "",
|
||||
"signature": "sha256:30bb811f79dc78fe63221c8960bb4237c811b94fdf197b6479709aff3244cb08"
|
||||
"signature": "sha256:e6a1d9a637dfbad45211a98a5bbc35255dc8f168a834ed466c363dfc384c0f59"
|
||||
},
|
||||
"nbformat": 3,
|
||||
"nbformat_minor": 0,
|
||||
|
|
@ -19,7 +19,31 @@
|
|||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"### String formatting - `.format()` vs. `%s`"
|
||||
"# Sections\n",
|
||||
"- [String formatting](#string_formatting)\n",
|
||||
" - [String formatting - .format() vs. binary operator %s](#str_format_bin)\n",
|
||||
" - [String Reversing - [::-1] vs. `''.join(reversed())`](#str_reverse)\n",
|
||||
"- [List Operations](#list_operations)\n",
|
||||
" - [List Reversing - [::-1] vs. reverse() vs. reversed()](#list_reverse)\n",
|
||||
"- [Dictionary Operations](#dict_ops) \n",
|
||||
" - [Adding elements to a dictionary](#adding_dict_elements)"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='string_formatting'></a>\n",
|
||||
"\n",
|
||||
"# String formatting"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='str_format_bin'></a>\n",
|
||||
"### String formatting - `.format()` vs. binary operator `%s`"
|
||||
]
|
||||
},
|
||||
{
|
||||
|
|
@ -74,6 +98,7 @@
|
|||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='str_reverse'></a>\n",
|
||||
"### String Reversing - `[::-1]` vs. `''.join(reversed())`"
|
||||
]
|
||||
},
|
||||
|
|
@ -129,6 +154,15 @@
|
|||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='list_operations'></a>\n",
|
||||
"# List Operations"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='list_reverse'></a>\n",
|
||||
"### List Reversing - `[::-1]` vs. `reverse()` vs. `reversed()`"
|
||||
]
|
||||
},
|
||||
|
|
@ -166,8 +200,8 @@
|
|||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"1000000 loops, best of 3: 857 ns per loop\n",
|
||||
"1000000 loops, best of 3: 1.78 \u00b5s per loop"
|
||||
"1000000 loops, best of 3: 930 ns per loop\n",
|
||||
"1000000 loops, best of 3: 1.89 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
|
|
@ -175,7 +209,7 @@
|
|||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"1000000 loops, best of 3: 758 ns per loop"
|
||||
"1000000 loops, best of 3: 775 ns per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
|
|
@ -186,7 +220,96 @@
|
|||
]
|
||||
}
|
||||
],
|
||||
"prompt_number": 10
|
||||
"prompt_number": 1
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='dict_ops'></a>\n",
|
||||
"# Dictionary Operations "
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='adding_dict_elements'></a>\n",
|
||||
"## Adding elements to a Dictionary"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"collapsed": false,
|
||||
"input": [
|
||||
"import random\n",
|
||||
"\n",
|
||||
"random.seed(123)\n",
|
||||
"rand_ints = [randrange(1, 10) for i in range(100)]\n",
|
||||
"\n",
|
||||
"def add_element_check1(my_dict, elements):\n",
|
||||
" for e in elements:\n",
|
||||
" if e not in my_dict:\n",
|
||||
" my_dict[e] = 1\n",
|
||||
" else:\n",
|
||||
" my_dict[e] += 1\n",
|
||||
" \n",
|
||||
"def add_element_check2(my_dict, elements):\n",
|
||||
" for e in elements:\n",
|
||||
" if e not in my_dict:\n",
|
||||
" my_dict[e] = 0\n",
|
||||
" my_dict[e] += 1 \n",
|
||||
"\n",
|
||||
"def add_element_except(my_dict):\n",
|
||||
" for e in elements:\n",
|
||||
" try:\n",
|
||||
" elements[e] += 1\n",
|
||||
" except KeyError:\n",
|
||||
" elements[e] = 1\n",
|
||||
" "
|
||||
],
|
||||
"language": "python",
|
||||
"metadata": {},
|
||||
"outputs": [
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"1\n",
|
||||
"5\n",
|
||||
"2\n",
|
||||
"7\n",
|
||||
"5\n",
|
||||
"2\n",
|
||||
"1\n",
|
||||
"7\n",
|
||||
"9\n",
|
||||
"9\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"6\n",
|
||||
"6\n",
|
||||
"1\n",
|
||||
"3\n",
|
||||
"3\n",
|
||||
"6\n",
|
||||
"9\n",
|
||||
"6\n",
|
||||
"4\n",
|
||||
"3\n"
|
||||
]
|
||||
}
|
||||
],
|
||||
"prompt_number": 16
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"collapsed": false,
|
||||
"input": [],
|
||||
"language": "python",
|
||||
"metadata": {},
|
||||
"outputs": [],
|
||||
"prompt_number": 15
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
|
|
|
|||
|
|
@ -1,7 +1,7 @@
|
|||
{
|
||||
"metadata": {
|
||||
"name": "",
|
||||
"signature": "sha256:30bb811f79dc78fe63221c8960bb4237c811b94fdf197b6479709aff3244cb08"
|
||||
"signature": "sha256:629f08ba90badbccee0e3581db0e76c716d0b93abc92869d2dc5176ac6b02854"
|
||||
},
|
||||
"nbformat": 3,
|
||||
"nbformat_minor": 0,
|
||||
|
|
@ -19,7 +19,31 @@
|
|||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"### String formatting - `.format()` vs. `%s`"
|
||||
"# Sections\n",
|
||||
"- [String formatting](#string_formatting)\n",
|
||||
" - [String formatting - .format() vs. binary operator %s](#str_format_bin)\n",
|
||||
" - [String Reversing - [::-1] vs. `''.join(reversed())`](#str_reverse)\n",
|
||||
"- [List Operations](#list_operations)\n",
|
||||
" - [List Reversing - [::-1] vs. reverse() vs. reversed()](#list_reverse)\n",
|
||||
"- [Dictionary Operations](#dict_ops) \n",
|
||||
" - [Adding elements to a dictionary](#adding_dict_elements)"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='string_formatting'></a>\n",
|
||||
"\n",
|
||||
"# String formatting"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='str_format_bin'></a>\n",
|
||||
"### String formatting - `.format()` vs. binary operator `%s`"
|
||||
]
|
||||
},
|
||||
{
|
||||
|
|
@ -74,6 +98,7 @@
|
|||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='str_reverse'></a>\n",
|
||||
"### String Reversing - `[::-1]` vs. `''.join(reversed())`"
|
||||
]
|
||||
},
|
||||
|
|
@ -129,6 +154,15 @@
|
|||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='list_operations'></a>\n",
|
||||
"# List Operations"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='list_reverse'></a>\n",
|
||||
"### List Reversing - `[::-1]` vs. `reverse()` vs. `reversed()`"
|
||||
]
|
||||
},
|
||||
|
|
@ -166,8 +200,8 @@
|
|||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"1000000 loops, best of 3: 857 ns per loop\n",
|
||||
"1000000 loops, best of 3: 1.78 \u00b5s per loop"
|
||||
"1000000 loops, best of 3: 930 ns per loop\n",
|
||||
"1000000 loops, best of 3: 1.89 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
|
|
@ -175,7 +209,7 @@
|
|||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"1000000 loops, best of 3: 758 ns per loop"
|
||||
"1000000 loops, best of 3: 775 ns per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
|
|
@ -186,7 +220,186 @@
|
|||
]
|
||||
}
|
||||
],
|
||||
"prompt_number": 10
|
||||
"prompt_number": 1
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='dict_ops'></a>\n",
|
||||
"# Dictionary Operations "
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<a name='adding_dict_elements'></a>\n",
|
||||
"## Adding elements to a Dictionary\n",
|
||||
"\n",
|
||||
"All three functions below count how often different elements (values) occur in a list. \n",
|
||||
"E.g., for the list ['a', 'b', 'a', 'c'], the dictionary would look like this: \n",
|
||||
"`my_dict = {'a': 2, 'b': 1, 'c': 1}`"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"collapsed": false,
|
||||
"input": [
|
||||
"import random\n",
|
||||
"import copy\n",
|
||||
"import timeit\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"def add_element_check1(my_dict, elements):\n",
|
||||
" for e in elements:\n",
|
||||
" if e not in my_dict:\n",
|
||||
" my_dict[e] = 1\n",
|
||||
" else:\n",
|
||||
" my_dict[e] += 1\n",
|
||||
" \n",
|
||||
"def add_element_check2(my_dict, elements):\n",
|
||||
" for e in elements:\n",
|
||||
" if e not in my_dict:\n",
|
||||
" my_dict[e] = 0\n",
|
||||
" my_dict[e] += 1 \n",
|
||||
"\n",
|
||||
"def add_element_except(my_dict, elements):\n",
|
||||
" for e in elements:\n",
|
||||
" try:\n",
|
||||
" my_dict[e] += 1\n",
|
||||
" except KeyError:\n",
|
||||
" my_dict[e] = 1\n",
|
||||
" \n",
|
||||
"\n",
|
||||
"random.seed(123)\n",
|
||||
"rand_ints = [randrange(1, 10) for i in range(100)]\n",
|
||||
"empty_dict = {}\n",
|
||||
"\n",
|
||||
"print('Results for 100 integers in range 1-10') \n",
|
||||
"%timeit add_element_check1(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
"%timeit add_element_check2(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
"%timeit add_element_except(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
" \n",
|
||||
"print('\\nResults for 1000 integers in range 1-10') \n",
|
||||
"rand_ints = [randrange(1, 10) for i in range(1000)]\n",
|
||||
"empty_dict = {}\n",
|
||||
"\n",
|
||||
"%timeit add_element_check1(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
"%timeit add_element_check2(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
"%timeit add_element_except(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
"\n",
|
||||
"print('\\nResults for 1000 integers in range 1-1000') \n",
|
||||
"rand_ints = [randrange(1, 10) for i in range(1000)]\n",
|
||||
"empty_dict = {}\n",
|
||||
"\n",
|
||||
"%timeit add_element_check1(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
"%timeit add_element_check2(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
"%timeit add_element_except(copy.deepcopy(empty_dict), rand_ints)\n",
|
||||
"\n",
|
||||
"# Python 3.4.0\n",
|
||||
"# MacOS X 10.9.2\n",
|
||||
"# 2.4 GHz Intel Core Duo\n",
|
||||
"# 8 GB 1067 Mhz DDR3\n",
|
||||
"#"
|
||||
],
|
||||
"language": "python",
|
||||
"metadata": {},
|
||||
"outputs": [
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"Results for 100 integers in range 1-10\n",
|
||||
"10000 loops, best of 3: 30.5 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"10000 loops, best of 3: 32.4 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"10000 loops, best of 3: 31.7 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"\n",
|
||||
"Results for 1000 integers in range 1-10\n",
|
||||
"1000 loops, best of 3: 241 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"1000 loops, best of 3: 247 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"1000 loops, best of 3: 209 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"\n",
|
||||
"Results for 1000 integers in range 1-1000\n",
|
||||
"1000 loops, best of 3: 241 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"1000 loops, best of 3: 247 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n",
|
||||
"1000 loops, best of 3: 206 \u00b5s per loop"
|
||||
]
|
||||
},
|
||||
{
|
||||
"output_type": "stream",
|
||||
"stream": "stdout",
|
||||
"text": [
|
||||
"\n"
|
||||
]
|
||||
}
|
||||
],
|
||||
"prompt_number": 25
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"### Conclusion\n",
|
||||
"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."
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user