Community Data Science Workshops (Fall 2014)/Day 1 lecture

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Welcome to the Saturday lecture section of the Community Data Science Workshop! For about 2 hours, we'll work through an introduction to the Python programming language via both a lecture and hand-on exercises.

Resources

Lecture outline

Review Friday material

  • math: using python as a calculator
    • addition, subtraction, multiplication, division
    • division shows something different: 8/2 versus 1/2
  • type()
    • there are different types of things in python (called objects)
    • variables that "know about the decimal place" (int) and variables that don't (floats)
  • variables
    • assignment of variaibles
    • e.g., math with variables: scale up a recipe, into an assignment
    • you can assign to a variable and it will replace the old value
  • strings
    • things within quotation marks
    • adding strings with "concatination" (smushing things together)
    • e.g., print("Hello" + name)
    • concatenating strings and integers don't work (e.g., print(1 + "mako"))
    • 1 is different than "1"; name is different than "name"
    • single quotes versus double quotes (python doesn't care)
    • you can also multiply strings! (although it's not clear why you want to weird)
  • booleans
    • comparisons (e.g., 1 == 1 or 1 == 0)
      • you can compare strings (case sensative!)
      • also >, <, and !=
    • type() shows that the output of True or False is bool
    • e.g., "i" in "team"
    • e.g., "i" not in "team"
  • if/elif/else
    • if, something that evaluates to a boolean, and then colon
    • e.g., if "mako" in "makoshark"
    • e.g., if mako_age > atom_age
    • indent with spaces (we use 4 spaces!)
  • functions
    • has a parentheses
    • we've already learnd examples of this: exit(), help(), type()

Lists

  1. lists
    • purpose
    • initialization
    • len() review
    • accessing elements
    • adding elements
    • changing elements
    • slicing lists
    • strings are like lists
      • len()
        • len("") length of the empty string
  2. loops and more flow control
    • for loops
    • if statements inside for loops
    • nested for loops
    • range()
    • while loops
    • infinite loops
    • if statements inside while loops
    • break
    • raw_input()
  3. dictionaries
    • purpose
    • initialization
    • accessing elements
    • adding elements
    • changing elements
    • keys() and values()
  4. modules
    • purpose
    • builtins
    • imports
    • import random
    • random.randint
    • random.choice
    • walk through state_capitals.py

Where state_capitals.py from http://mako.cc/teaching/2014/cdsw/state_capitals.py is the grand finale and synthesis of lecture material.

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