Newer
Older
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Einführung in Python und NumPy"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Variablen und Datentypen in Python"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Primitive Datentypen"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"a = 5\n",
"b = \"Hello World\"\n",
"c = 3.14\n",
"d = True\n",
"e = 4 + 3j\n",
"print(a, b, c, d, e)\n",
"print(type(a), type(b), type(c), type(d), type(e))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Variablen überschreiben"
]
},
{
"cell_type": "code",
"source": [
"var = 50\n",
"print(var)\n",
"var = \"Hello World\" # Neuer Datentyp\n",
"print(var)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Mehrere Variablen initialisieren"
]
},
{
"cell_type": "code",
"source": [
"x, y, z = 5, 6, 7\n",
"i = j = k = \"ha\"\n",
"print(x, y, z)\n",
"print(i, j, k)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Variablen tauschen"
]
},
{
"cell_type": "code",
"source": [
"a, b = 1, 2\n",
"a, b = b, a\n",
"print(b)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Operatoren"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"a, b = 2, 4\n",
"print(a + b)\n",
"print(a - b)\n",
"print(a * b)\n",
"print(a / b)\n",
"print(a // b)\n",
"print(a % b)\n",
"print(a**b)\n",
"print(b**(1/a))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Variablen mit Operatoren neu zuweisen"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"i = j = k = 7\n",
"i += 5\n",
"j *= 5\n",
"k **= 5\n",
"print(i, j, k)\n",
"# Kein i++"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Boolesche Operatoren"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(1 + 1 == 2)\n",
"print(1 + 2 != 2)\n",
"print(1 + 2 > 3)\n",
"print(1 + 2 <= 3)\n",
"print(1 + 2 is 3)\n",
"print(True or False) # ||\n",
"print(True and False) # &&\n",
"print(not True) # !"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Listen"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"l = [\"python\", \"numpy\", \"scipy\", 10, True]\n",
"print(l[0], l[1], l[2], l[3], l[4])\n",
"print(l[-1], l[-2], l[-3], l[-4], l[-5])\n",
"print(len(l))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Listen bearbeiten"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"scrolled": true
},
"source": [
"l.append(False)\n",
"print(l)\n",
"l[3] = \"matplotlib\"\n",
"print(l)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Operatoren auf Listen"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"l1, l2 = [1,2,3,4], [5,6,7,8]\n",
"l = l1 + l2\n",
"print(l)\n",
"print(3 * l1)\n",
"print(5 in l2)\n",
"print(5 in l1)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Mehrdimensionale Listen"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"A = [[1,2,3], [4,5,6], [7,8,9]]\n",
"print(A[0][0], A[1][0], A[1][2])\n",
"print(A[0], A[1], A[2])"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### List Slices\n",
"Notation: liste[start: stop: step]"
]
},
{
"cell_type": "code",
"execution_count": null,
"print(l[2:5]) # der Index von stop ist nicht mit dabei\n",
"print(l[2:]) # stop weglassen => bis zum Ende\n",
"print(l[:5]) # start weglassen => vom Anfang an\n",
"print(l[2:5:2]) # Das erste Element (start) ist immer mit dabei\n",
"print(l[5:2:-1])\n",
"print(l[::-1])"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Tupel"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"t = (\"Audi\", 250, 4.7, True)\n",
"print(t[0], t[1], t[2], t[3])\n",
"print(t[-1], t[-2], t[-3], t[-4])\n",
"print(len(t))\n",
"print(\"Audi\" in t)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Tupel können nicht verändert werden, nur zusammengefügt!"
]
},
{
"cell_type": "code",
"execution_count": null,
"t += (\"white\",) # es wird ein neues Tupel erstellt\n",
"print(t)\n",
"a, b, c, d, e = t\n",
"print(c, e)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Dictionaries"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"scrolled": true
},
"source": [
"c = {\n",
" \"brand\": \"Audi\",\n",
" \"ps\": 250,\n",
" \"acc\": 4.7\n",
"}\n",
"\n",
"c[\"color\"] = \"white\"\n",
"\n",
"print(c[\"brand\"])\n",
"print(c.keys())\n",
"print(c.values())\n",
"print(c.items()) "
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Funktionen und Verzweigungen"
]
},
{
"cell_type": "code",
"execution_count": null,
" print(\"Hello world\")\n",
"\n",
"greet()"
]
},
{
"cell_type": "code",
"execution_count": null,
"def square(x: int) -> int:\n",
" return x**2\n",
"\n",
"print(square(4))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Optionale Parameter und Parameter mit Namen"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"def pow(x, y = 0):\n",
" return x**y\n",
"\n",
"print(pow(10))\n",
"print(pow(10, 2))\n",
"print(pow(y=2, x=5))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Mehrere Rückgabewerte (Tupel)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"def f(x, y):\n",
" return x**2, y**2\n",
"\n",
"a, b = f(3, 4)\n",
"print(a, b)\n",
"ab = f(3, 4)\n",
"print(ab)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Bedingte Anweisungen"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"def sign(x):\n",
" if x < 0:\n",
" return -1\n",
" elif x > 0:\n",
" return 1\n",
" else:\n",
" return 0\n",
" \n",
"print(sign(17), sign(-3), sign(0))"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"def positive(x):\n",
" return True if x > 0 else False\n",
"\n",
"print(positive(14), positive(0))\n",
"\n",
"# C/Java return x > 0 ? True : False"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Schleifen"
]
},
{
"cell_type": "code",
"execution_count": null,
"for i in range(5): # Python For-Schleifen iterieren immer über ein iterable z.B. Liste\n",
" print(i)\n",
" \n",
"print(list(range(1, 6)))\n",
"print(list(range(1, 10, 2)))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Funktionsweise: range(start, stop, step)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### List Comprehensions"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"a = [i**2 for i in range(5)]\n",
"print(a)\n",
"\n",
"b = [i**2 for i in range(10) if i % 2 == 0]\n",
"print(b)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Über Datenstrukturen iterieren"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(l2)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"for el in l2:\n",
" print(el)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"for i in range(len(l2)):\n",
" print(i, l2[i])"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"for i, el in enumerate(l2):\n",
" print(i, el)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(c)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"for key, val in c.items():\n",
" print(key, val)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Objektorientierte Programmierung"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"class Person:\n",
" def __init__(self, name):\n",
" self.name = name\n",
" \n",
" def greet(self):\n",
" print(\"Hallo, ich bin {}\".format(self.name))\n",
" \n",
" def __repr__(self):\n",
" return \"Person: {}\".format(self.name)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"p = Person(\"Anna\")\n",
"p.greet()\n",
"print(p)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"class Student(Person):\n",
" def __init__(self, name, age, height):\n",
" Person.__init__(self, name)\n",
" self.__age = age # private\n",
" self._height = height # protected\n",
" \n",
" def __repr__(self):\n",
" return \"Person[name={},age={},height={}]\"\\\n",
" .format(self.name, self.__age, self._height)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"s = Student(\"Anna\", 18, 175)\n",
"s.greet()\n",
"print(s)\n",
"# print(s.__age)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Funktionale Programmierung"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"g = lambda x: x**4\n",
"h = lambda x, y: x**(2*y)\n",
"print(g(3))\n",
"print(h(2,2))"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(l)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"lsq = map(lambda x: x**2, l)\n",
"print(lsq)\n",
"print(list(lsq))"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(list(filter(lambda x: x % 2 == 1, l)))"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"from functools import reduce\n",
"print(reduce(lambda a, b: a + b, l))"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(reduce(lambda a, b: a if a > b else b, l))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## == vs. is"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(5 == 5)\n",
"print(5 is 5)"
]
},
{
"cell_type": "code",
"execution_count": null,
"print([1,2,3] is [1,2,3])\n",
"print(a is b)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## NumPy Grundlagen"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"import numpy as np"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### NumPy Arrays"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"a = np.array([1, 2, 3, 4, 5, 6])\n",
"print(a)\n",
"print(a[0])\n",
"print(a[-1])\n",
"print(a[1:4])\n",
"print(a[:2])\n",
"print(a[::-1])\n",
"print(a[1::2])\n",
"print(a[[0, 2, 3, 4]]) # Liste von Indizes\n",
"print(a[[True, False, True, False, False, True]])"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Operatoren auf NumPy Arrays"
]
},
{
"cell_type": "code",
"execution_count": null,
"print(a + 2)\n",
"print(3 * a)\n",
"print(a**2)\n",
"print(2**a)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"b = np.array([6, 5, 4, 3, 2, 1]) # b = a[::-1]"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(a + b)\n",
"print(a * b)\n",
"print(a**b)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Zweidimensionale Arrays (Matrizen)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"A = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])\n",
"print(A)\n",
"print(A[0,0], A[1, 2])"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(A[0])\n",
"print(A[:, 0])"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(A[:2, :2])"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(A[:2, 1::-1])"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(A[1::-1, :2])"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Werte überschreiben"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"B = A.copy()\n",
"print(B)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"B[0] = 12\n",
"print(B)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"B[:, 1] = -5\n",
"print(B)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"B[2] = [5, 6, 7]\n",
"print(B)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"B[:, 1] = B[0]\n",
"print(B)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Dimensionen hinzufügen"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(A[None])"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(A[:, None])"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(A[:, :, None])"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"X = np.array([[1,0],[0,1]])\n",
"Y = np.array([[1,1],[2,1],[3,4]])\n",
"print(X[:, None] - Y[None, :])\n",
"print(X[None, :] - Y[:, None])"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Boolesche Funktionen auf NumPy Arrays"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"b = np.array([1, 0, 1])"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(b == 1)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(b < 1)"
]
},
{
"cell_type": "code",
"execution_count": null,
"source": [
"print(A[b == 1])"
]
},