{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"On disait que \n",
"* Python est un langage de programmation **interprété, multi-paradigme et multiplateformes**\n",
"* Il favorise la **programmation impérative structurée, fonctionnelle et orientée objet**\n",
"\n",
"Source: https://fr.wikipedia.org/wiki/Python_(langage)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Les fonctions"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Déclaration"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {},
"outputs": [],
"source": [
"def hello_world():\n",
" \n",
" return \"Hello world!\""
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Appel"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"'Hello world!'"
]
},
"execution_count": 2,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"hello_world()"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Hello world!\n"
]
}
],
"source": [
"a = hello_world()\n",
"print(a)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Documentation"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Help on function hello_world in module __main__:\n",
"\n",
"hello_world()\n",
"\n"
]
}
],
"source": [
"help(hello_world)"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {},
"outputs": [],
"source": [
"def hello_world():\n",
" \"\"\"\n",
" This function sends a welcome message to the user.\n",
" \"\"\"\n",
" \n",
" return \"Hello world!\""
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Help on function hello_world in module __main__:\n",
"\n",
"hello_world()\n",
" This function sends a welcome message to the user.\n",
"\n"
]
}
],
"source": [
"help(hello_world)"
]
},
{
"cell_type": "code",
"execution_count": 7,
"metadata": {},
"outputs": [],
"source": [
"# cf. https://numpydoc.readthedocs.io/en/latest/format.html#docstring-standard\n",
"\n",
"def hello_world( n ):\n",
" \"\"\"\n",
" This function sends a welcome message to the user.\n",
" \n",
" Parameters\n",
" ----------\n",
" n : integer\n",
" the number of repetitions\n",
"\n",
" Returns\n",
" -------\n",
" string\n",
" a value in a string\n",
" \"\"\"\n",
" \n",
" return \"Hello world! \" * n"
]
},
{
"cell_type": "code",
"execution_count": 8,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Help on function hello_world in module __main__:\n",
"\n",
"hello_world(n)\n",
" This function sends a welcome message to the user.\n",
" \n",
" Parameters\n",
" ----------\n",
" n : integer\n",
" the number of repetitions\n",
" \n",
" Returns\n",
" -------\n",
" string\n",
" a value in a string\n",
"\n"
]
}
],
"source": [
"help(hello_world)"
]
},
{
"cell_type": "code",
"execution_count": 9,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"'Hello world! Hello world! '"
]
},
"execution_count": 9,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"hello_world(2)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### _Type hints_ (Python 3.5+)\n",
"cf. https://realpython.com/documenting-python-code/"
]
},
{
"cell_type": "code",
"execution_count": 10,
"metadata": {},
"outputs": [],
"source": [
"def hello_world( n: int ) -> str:\n",
" \n",
" return \"Hello world! \" * n"
]
},
{
"cell_type": "code",
"execution_count": 11,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"'Hello world! Hello world! '"
]
},
"execution_count": 11,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"hello_world(2)"
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {},
"outputs": [
{
"ename": "TypeError",
"evalue": "can't multiply sequence by non-int of type 'str'",
"output_type": "error",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
"\u001b[0;31mTypeError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m<ipython-input-12-8c7890b5a99f>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mhello_world\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m\"2\"\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;32m<ipython-input-10-6ece3cdf1a2b>\u001b[0m in \u001b[0;36mhello_world\u001b[0;34m(n)\u001b[0m\n\u001b[1;32m 1\u001b[0m \u001b[0;32mdef\u001b[0m \u001b[0mhello_world\u001b[0m\u001b[0;34m(\u001b[0m \u001b[0mn\u001b[0m\u001b[0;34m:\u001b[0m \u001b[0mint\u001b[0m \u001b[0;34m)\u001b[0m \u001b[0;34m->\u001b[0m \u001b[0mstr\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 2\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0;32mreturn\u001b[0m \u001b[0;34m\"Hello world! \"\u001b[0m \u001b[0;34m*\u001b[0m \u001b[0mn\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mTypeError\u001b[0m: can't multiply sequence by non-int of type 'str'"
]
}
],
"source": [
"hello_world(\"2\")"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"http://mypy-lang.org/ $\\rightarrow$ \"_experimental optional static type checker for Python_\""
]
},
{
"cell_type": "code",
"execution_count": 13,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Help on function hello_world in module __main__:\n",
"\n",
"hello_world(n: int) -> str\n",
"\n"
]
}
],
"source": [
"help(hello_world)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Valeurs par défaut des arguments d'une fonction"
]
},
{
"cell_type": "code",
"execution_count": 14,
"metadata": {},
"outputs": [],
"source": [
"def add(a, b=10):\n",
" return a+b"
]
},
{
"cell_type": "code",
"execution_count": 15,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"3"
]
},
"execution_count": 15,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"add(1, 2)"
]
},
{
"cell_type": "code",
"execution_count": 16,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"11"
]
},
"execution_count": 16,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"add(1)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"N.B. :"
]
},
{
"cell_type": "code",
"execution_count": 17,
"metadata": {},
"outputs": [
{
"ename": "SyntaxError",
"evalue": "non-default argument follows default argument (<ipython-input-17-7e1ef5ad4f7a>, line 1)",
"output_type": "error",
"traceback": [
"\u001b[0;36m File \u001b[0;32m\"<ipython-input-17-7e1ef5ad4f7a>\"\u001b[0;36m, line \u001b[0;32m1\u001b[0m\n\u001b[0;31m def add(a=10, b):\u001b[0m\n\u001b[0m ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m non-default argument follows default argument\n"
]
}
],
"source": [
"def add(a=10, b):\n",
" return a+b"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Lors d'un appel, on peut passer les noms des arguments..."
]
},
{
"cell_type": "code",
"execution_count": 18,
"metadata": {},
"outputs": [],
"source": [
"def add(a=1, b=2):\n",
" print(\"a = \", a)\n",
" print(\"b = \", b)\n",
" return a+b"
]
},
{
"cell_type": "code",
"execution_count": 19,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"a = 1\n",
"b = 2\n"
]
},
{
"data": {
"text/plain": [
"3"
]
},
"execution_count": 19,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"add(1,2)"
]
},
{
"cell_type": "code",
"execution_count": 20,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"a = 2\n",
"b = 1\n"
]
},
{
"data": {
"text/plain": [
"3"
]
},
"execution_count": 20,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"add(b=1, a=2)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### `*args` et `**kwargs` \n",
"N.B. `*toto` et `**tata` marcheraient aussi !"
]
},
{
"cell_type": "code",
"execution_count": 21,
"metadata": {},
"outputs": [],
"source": [
"def my_function(*args, **kwargs):\n",
" print(\"arguments:\")\n",
" print(args)\n",
" print()\n",
" print(\"keyword arguments:\")\n",
" print(kwargs)"
]
},
{
"cell_type": "code",
"execution_count": 22,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"arguments:\n",
"(1, 2, 3)\n",
"\n",
"keyword arguments:\n",
"{'k1': 'v1', 'k2': 'v2'}\n"
]
}
],
"source": [
"my_function(1, 2, 3, k1=\"v1\", k2=\"v2\")"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Oui, on peut faire un mélange :"
]
},
{
"cell_type": "code",
"execution_count": 23,
"metadata": {},
"outputs": [],
"source": [
"def my_other_function(a, b, *args, **kwargs):\n",
" print(\"arguments:\")\n",
" print(args)\n",
" print()\n",
" print(\"keyword arguments:\")\n",
" print(kwargs)"
]
},
{
"cell_type": "code",
"execution_count": 24,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"arguments:\n",
"(3, 4)\n",
"\n",
"keyword arguments:\n",
"{'k1': 'v1'}\n"
]
}
],
"source": [
"my_other_function(1, 2, 3, 4, k1=\"v1\")"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Les fonctions `lambda`"
]
},
{
"cell_type": "code",
"execution_count": 25,
"metadata": {},
"outputs": [],
"source": [
"double = lambda x: x*2"
]
},
{
"cell_type": "code",
"execution_count": 26,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"20"
]
},
"execution_count": 26,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"double(10)"
]
},
{
"cell_type": "code",
"execution_count": 27,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"'hello hello '"
]
},
"execution_count": 27,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"double(\"hello \")"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Exemple d'application"
]
},
{
"cell_type": "code",
"execution_count": 28,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"['apple', 'raspberry', 'orange']"
]
},
"execution_count": 28,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"my_list = ['apple', 'raspberry', 'orange']\n",
"my_list"
]
},
{
"cell_type": "code",
"execution_count": 29,
"metadata": {},
"outputs": [],
"source": [
"my_list.sort( key = lambda x: len(x) )"
]
},
{
"cell_type": "code",
"execution_count": 30,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"['apple', 'orange', 'raspberry']"
]
},
"execution_count": 30,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"my_list"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.7.5"
}
},
"nbformat": 4,
"nbformat_minor": 2
}