518 lines
12 KiB
Plaintext
518 lines
12 KiB
Plaintext
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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {
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"nbgrader": {
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"grade": false,
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"grade_id": "cell-df7302b349aba739",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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}
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},
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"source": [
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"# Classes in Python\n",
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"\n",
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"First, let's consider some data in a plain Python dictionary:"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {
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"nbgrader": {
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"grade": false,
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"grade_id": "cell-5eb4e7d87487b636",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"car1 = {\n",
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" 'name': 'Fer',\n",
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" 'worth': 60000,\n",
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" 'type_': 'convertible',\n",
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" 'color': 'red'\n",
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"}\n",
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"car2 = {\n",
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" 'name': 'Jump',\n",
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" 'worth': 10000,\n",
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" 'type_': 'van',\n",
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" 'color': 'blue'\n",
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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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"execution_count": 2,
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"metadata": {
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"nbgrader": {
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"grade": false,
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"grade_id": "cell-b6fe8f994da7634c",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"'Fer'"
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]
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},
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"execution_count": 2,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"car1['name']"
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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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"nbgrader": {
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"grade": false,
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"grade_id": "cell-2b0e27117c238bca",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"source": [
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"Now, let's make a Python class which will hold this same kind of data:"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 3,
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"metadata": {
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"nbgrader": {
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"grade": false,
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"grade_id": "cell-17b8022fd73e630c",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"class Car:\n",
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" def __init__(self,name,worth,type_,color):\n",
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" self.name = name\n",
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" self.worth = worth\n",
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" self.type_ = type_\n",
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" self.color = color\n",
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" def print_car(self):\n",
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" print(\"%s is worth %d and is a %s %s.\"%(self.name, self.worth, self.color, self.type_))"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 4,
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"metadata": {
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"nbgrader": {
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"grade": false,
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"grade_id": "cell-98bd27b61013b730",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"car1 = Car(\"Fer\",60000,\"convertible\",\"red\")"
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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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"nbgrader": {
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"grade": false,
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"grade_id": "cell-1055b5581d221586",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"source": [
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"## Takeaway message\n",
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"\n",
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"- The data in an instances of a class are conceptually very similar to python dicts with a few special features. One of these special features is methods. Another is that you access instance variables with with the `x_instance.name` syntax instead of `x_dict['name']` syntax."
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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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"nbgrader": {
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"grade": false,
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"grade_id": "cell-ce0b6c546e3ec2d5",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"source": [
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"## Q1 creating an instance of a class\n",
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"\n",
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"We have a class defined for vehicles. Create two new vehicles (\"instances of the class\") with the variable names `car1` and `car2`. Set car1 to be a red convertible worth EUR 60,000.00 with a name of Fer, and car2 to be a blue van named Jump worth EUR 10,000.00."
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]
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},
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{
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"cell_type": "code",
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"execution_count": 5,
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"metadata": {
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"nbgrader": {
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"grade": false,
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"grade_id": "cell-ae7291a16e80887f",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"class Vehicle:\n",
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" def __init__(self, color, worth, name): \n",
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" self.color = color\n",
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" self.worth = worth\n",
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" self.name = name\n",
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" def get_description(self):\n",
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" return 'name: {}, worth: {}, color: {}'.format(self.name, self.worth, self.color)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 6,
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"metadata": {
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"nbgrader": {
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"grade": false,
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"grade_id": "cell-3f2711d5634d8201",
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"locked": false,
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"schema_version": 3,
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"solution": true,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"car1 = Vehicle('red', 60000, 'Fer')\n",
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"car2 = Vehicle('blue', 10000, 'Jump')"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 7,
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"metadata": {
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"nbgrader": {
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"grade": true,
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"grade_id": "cell-081ffcbe096c0760",
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"locked": true,
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"points": 1,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"# This checks if your code works. Do not change it. It should run without error.\n",
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"assert( car1.get_description()==\"name: Fer, worth: 60000, color: red\" )\n",
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"assert( car2.get_description()==\"name: Jump, worth: 10000, color: blue\" )"
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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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"nbgrader": {
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"grade": false,
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"grade_id": "cell-634909b4b67c316a",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"source": [
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"## Q2 creating a class\n",
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"\n",
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"Create a class called `Pet`. The `__init__` function should take 3 arguments: `self`, `name`, and `sound`. The `name`, and `sound` arguments should be assigned to the instance variables `self.name` and `self.sound`."
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]
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},
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{
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"cell_type": "code",
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"execution_count": 8,
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"metadata": {
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"nbgrader": {
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"grade": false,
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"grade_id": "cell-6976ffa1c6d95602",
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"locked": false,
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"schema_version": 3,
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"solution": true,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"class Pet:\n",
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" def __init__(self, name, sound):\n",
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" self.name = name\n",
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" self.sound = sound"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 9,
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"metadata": {
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"nbgrader": {
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"grade": true,
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"grade_id": "cell-c49bb38441eca03a",
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"locked": true,
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"points": 1,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"# This checks if your code works. Do not change it. It should run without error.\n",
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"my_pet = Pet('Bob', 'talk')\n",
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"assert(my_pet.name=='Bob')\n",
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"assert(my_pet.sound=='talk')"
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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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"nbgrader": {
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"grade": false,
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"grade_id": "cell-f34bb63b09eccd59",
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"locked": true,
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"schema_version": 3,
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"solution": false,
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"task": false
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}
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},
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"source": [
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"## Q3 writing a method\n",
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"\n",
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"Now, create a new class called `NoisyPet`. The `__init__` function should be like in `Pet`. (It takes 3 arguments: `self`, `name`, and `sound`. The `name`, and `sound` arguments should be assigned to the instance variables `self.name` and `self.sound`.)\n",
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"\n",
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"`NoisyPet` should have an additional method called `make_noise` which takes zero additional arguments (of course `self` is required). The `make_noise` for a name of `\"cricket\"` and sound of `\"chirp\"`, this method should return a string like `\"My pet cricket makes a noise like chirp\"`. Thus, you will need to return a string you have created using string formatting."
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]
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},
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{
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"cell_type": "code",
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"execution_count": 10,
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"metadata": {
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"nbgrader": {
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||
|
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"grade": false,
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"grade_id": "cell-30ebdf29d3de2e41",
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"locked": false,
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"schema_version": 3,
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"solution": true,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"class NoisyPet:\n",
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" def __init__(self, name, sound):\n",
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" self.name = name\n",
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" self.sound = sound\n",
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" def make_noise(self):\n",
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" return \"My pet {} makes a noise like {}\".format(self.name, self.sound)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 11,
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"metadata": {
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"nbgrader": {
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||
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"grade": true,
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||
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"grade_id": "cell-232b938072cf100c",
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||
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"locked": true,
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"points": 1,
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"schema_version": 3,
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||
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"solution": false,
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"task": false
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}
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},
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"outputs": [],
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"source": [
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"# This checks if your code works. Do not change it. It should run without error.\n",
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"assert(NoisyPet(\"cricket\", \"chirp\").make_noise()==\"My pet cricket makes a noise like chirp\")"
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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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"nbgrader": {
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"grade": false,
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"grade_id": "cell-ded0dd503cbcd3b7",
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"locked": true,
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"schema_version": 3,
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||
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"solution": false,
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||
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"task": false
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||
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}
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},
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"source": [
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"## Q4 using instances 1\n",
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"\n",
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"Now create a list named `my_pets` with 5 instances of the NoisyPet class given the following names and noises.\n",
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"\n",
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"| name | noise |\n",
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"| --- | --- |\n",
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"| Fido | slobber |\n",
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"| Mr. Skinny Legs | (silent) |\n",
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"| cricket | chirp |\n",
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"| Adelheid | cackle |\n",
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"| Bello | bark |"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 12,
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||
|
|
"metadata": {
|
||
|
|
"nbgrader": {
|
||
|
|
"grade": false,
|
||
|
|
"grade_id": "cell-9e7de69ef49036d8",
|
||
|
|
"locked": false,
|
||
|
|
"schema_version": 3,
|
||
|
|
"solution": true,
|
||
|
|
"task": false
|
||
|
|
}
|
||
|
|
},
|
||
|
|
"outputs": [],
|
||
|
|
"source": [
|
||
|
|
"my_pets = [\n",
|
||
|
|
" NoisyPet(\"Fido\", \"slobber\"),\n",
|
||
|
|
" NoisyPet(\"Mr. Skinny Legs\", \"(silent)\"),\n",
|
||
|
|
" NoisyPet(\"cricket\", \"chirp\"),\n",
|
||
|
|
" NoisyPet(\"Adelheid\", \"cackle\"),\n",
|
||
|
|
" NoisyPet(\"Bello\", \"bark\"),\n",
|
||
|
|
"]"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"execution_count": 13,
|
||
|
|
"metadata": {
|
||
|
|
"nbgrader": {
|
||
|
|
"grade": true,
|
||
|
|
"grade_id": "cell-ef3307b4ff8e4134",
|
||
|
|
"locked": true,
|
||
|
|
"points": 1,
|
||
|
|
"schema_version": 3,
|
||
|
|
"solution": false,
|
||
|
|
"task": false
|
||
|
|
}
|
||
|
|
},
|
||
|
|
"outputs": [],
|
||
|
|
"source": [
|
||
|
|
"# This checks if your code works. Do not change it. It should run without error.\n",
|
||
|
|
"assert(type(my_pets)==list)\n",
|
||
|
|
"assert(len(my_pets)==5)\n",
|
||
|
|
"for my_pet in my_pets:\n",
|
||
|
|
" assert(isinstance(my_pet,NoisyPet))\n",
|
||
|
|
" my_pet.make_noise()"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"nbgrader": {
|
||
|
|
"grade": false,
|
||
|
|
"grade_id": "cell-7f3ab5609b4c6d4b",
|
||
|
|
"locked": true,
|
||
|
|
"schema_version": 3,
|
||
|
|
"solution": false,
|
||
|
|
"task": false
|
||
|
|
}
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"## Q5 using instances 2\n",
|
||
|
|
"\n",
|
||
|
|
"Now create a function list named `get_pet_name_length` which takes a single argument, which is an instance of the NoisyPet class. It should return the number of letters in the pet's name."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"execution_count": 14,
|
||
|
|
"metadata": {
|
||
|
|
"nbgrader": {
|
||
|
|
"grade": false,
|
||
|
|
"grade_id": "cell-4fb1927bd55587b9",
|
||
|
|
"locked": false,
|
||
|
|
"schema_version": 3,
|
||
|
|
"solution": true,
|
||
|
|
"task": false
|
||
|
|
}
|
||
|
|
},
|
||
|
|
"outputs": [],
|
||
|
|
"source": [
|
||
|
|
"def get_pet_name_length(pet):\n",
|
||
|
|
" return len(pet.name)"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"execution_count": 15,
|
||
|
|
"metadata": {
|
||
|
|
"nbgrader": {
|
||
|
|
"grade": true,
|
||
|
|
"grade_id": "cell-adabc63962b7ba48",
|
||
|
|
"locked": true,
|
||
|
|
"points": 1,
|
||
|
|
"schema_version": 3,
|
||
|
|
"solution": false,
|
||
|
|
"task": false
|
||
|
|
}
|
||
|
|
},
|
||
|
|
"outputs": [],
|
||
|
|
"source": [
|
||
|
|
"# This checks if your code works. Do not change it. It should run without error.\n",
|
||
|
|
"assert(get_pet_name_length(NoisyPet(\"Bello\", \"bark\"))==5)\n",
|
||
|
|
"assert(get_pet_name_length(NoisyPet(\"cricket\", \"chirp\"))==7)"
|
||
|
|
]
|
||
|
|
}
|
||
|
|
],
|
||
|
|
"metadata": {
|
||
|
|
"celltoolbar": "Create Assignment",
|
||
|
|
"kernelspec": {
|
||
|
|
"display_name": "Python 3 (ipykernel)",
|
||
|
|
"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": "3.11.10"
|
||
|
|
}
|
||
|
|
},
|
||
|
|
"nbformat": 4,
|
||
|
|
"nbformat_minor": 4
|
||
|
|
}
|