Packages

• lots of useful functions
  • add ons
• method 1
  • import(package)
  • package.function(x)
• method 2
  • from package import function
    • from package import * to import all from a package
  • function(x)
    • no need to call "math." before calling a function from the math package

Method 1 example

import math
math.sqrt(x)

• import = function
• math = package imported
• math.sqrt(x) takes the square root of x
• need to specify that you're using the math package by specifying "math." before you call any function

Method 2 example

# if you want to import one function
from math import sqrt
sqrt(x)
# if you want to import all functions from a library
from math import *
sqrt (x)

• specify which function you want to import from the math package
• don't need to call "math." when calling on any functions from the math package

Using IDLE

• What is IDLE?
  • a text editor with syntax highlighting (for Python only)
• Using IDLE to write your first program
  • Select "File", which should be on the top of your screen, then click "new file"
  • Write your code in the new file
  • Select "Run", which should be on the top of your screen, then select "Run Module
  • If prompted to save the file, just click "ok" and save the file
  • "why isn't anything I'm doing showing up on the screen?"
  • remember that you have to call a print statement on the things that you've done in order for them to show up on the screen

Variables

• Python reads LINE BY LINE
  • If you define a variable twice, it will only take the newest definition
• variable types
  • string
    • NOT interpreted by Python (Python doesn't try to find meaning from strings)
  • integers/int
    • whole numbers, can be negative
  • float
    • numbers with decimal places

User Input

x = input("prompt")

• Gives the user the prompt "prompt", then allows the user to submit user input, then assigns the input to the variable x
• Note: the input will be automatically assigned as a string. If another type is required, you need to transform the input into the type desired
  • e.g. int(input("prompt"))

Printing strings + variables together

print("string  " , variable , " string")
>>> string variable string

• Separate the different elements using a comma
• Remember to leave spaces if needed, Python does not automatically account for spaces when adding strings and variables together

Homework

Find the most impressive Scratch/Minecraft computing project you've done before. Be ready to present this tomorrow.