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192 lines
4.4 KiB
192 lines
4.4 KiB
# Intro to Python pt. 2
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## Lesson Objectives
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1. Get user input
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1. Repeatedly perform a set of commands
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1. Use a for loop
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1. Define a function
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1. Create a class for an object
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1. Have a class inherit from another
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1. Create a factory for objects
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## Get user input
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You can get user input from the command like so:
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```python
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user_input = input("Please enter your name: ")
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print("Hello, " + user_input + "!")
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```
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## Repeatedly perform a set of commands
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```python
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a = 10
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while a < 20:
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print("the value of a is currently: " + str(a))
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a += 1
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```
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### ACTIVITY
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1. Write a program that models this flow chart:
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## Use a for loop
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The process of looping through an array can be simplified with a `for` loop:
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```python
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foods = ['hot dogs', 'beer', 'bald eagles']
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for food in foods:
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print(food)
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```
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You can loop through a set of numbers using a `range`
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```python
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for x in range(0, 3):
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print(x)
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```
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### ACTIVITIES
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1. Given the following list [70, 95, 97, 55, 3, 24, 89, 97, 84, 11]
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- Write a program that loops through each value in the list and prints it
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- Write a program that loops through each value in the list and adds them all together
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- Write a program that loops through each value in the list and prints the average
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- Write a program that loops through each value in the list and prints the minimum
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- Write a program that loops through each value in the list and prints the maximum
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1. Combine all the programs from the previous step into one program that asks the user what operation they would like to do
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1. Alter the last program so that it performs the operations for only numbers that are greater than a number specified by the user
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## Define a function
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If you have a routine that you run over and over again, you can define your own function:
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```python
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def greet():
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print('hi')
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greet()
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```
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Functions can take parameters which alter their functionality:
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```python
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def greet(name):
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print('hi, ' + name)
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greet('bob')
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```
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Functions can return values:
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```python
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def add(value1, value2):
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return value1 + value2
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print(add(1,3))
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```
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### ACTIVITIES
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Create a calculator program that continually asks a user what operations they want to perform, until the user says 'quit'
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## Create a class for an object
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You can use a `class` or blueprint for objects that you'll use
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```python
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class Person:
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def __init__(self, name, age):
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self.name = name
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self.age = age
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def greet(self):
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print("Hello, my name is " + self.name + ". My age is " + str(self.age))
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me = Person("Hunter", 29)
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me.greet()
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sally = Person("Sally", 53)
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sally.greet()
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```
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- `__init__` is a function that gets called when a new object is created. Make sure you use two underscores on either side of the `init` or it will break!
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- `self` is the object that's created
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## Have a class inherit from another
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```python
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class Person:
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def __init__(self, name, age):
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self.name = name
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self.age = age
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def greet(self):
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print("Hello, my name is " + self.name + ". My age is " + str(self.age))
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def work(self):
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print("Boring...")
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class SuperHero(Person): # tell it to inherit from Person
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def __init__(self, name, age, powers):
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super().__init__(name,age) # call Person's __init__()
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self.powers = powers
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def greet(self):
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super().greet() # call Person's greet()
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self.listPowers()
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def listPowers(self):
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for power in self.powers:
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print(power)
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def work(self): # override Person's work()
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print("To action!")
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superman = SuperHero('Clark Kent', 200, ['flight', 'strength', 'invulnerability'])
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superman.greet()
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superman.work()
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```
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## Create a factory for objects
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```python
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class Car:
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def __init__(self, maker, model, serial):
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self.maker = maker
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self.model = model
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self.serial = serial
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class CarFactory:
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def __init__(self, name):
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self.name = name
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self.cars = []
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def makeCar(self, model):
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self.cars.append(Car(self.name, model, len(self.cars)))
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def listCars(self):
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for car in self.cars:
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print(car.maker + " " + car.model + " serial#: " + str(car.serial))
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def findCar(self, serial):
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for car in self.cars:
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if(car.serial == serial):
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return car
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toyota = CarFactory('Toyota')
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toyota.makeCar('Prius')
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toyota.makeCar('Rav 4')
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toyota.listCars()
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print(toyota.findCar(1).model)
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```
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