Class 3A: Introduction to Programming in Python

We will begin soon! Until then, feel free to use the chat to socialize, and enjoy the music!

Photo by Christina Morillo from Pexels

Firas Moosvi

Class Outline:

• Announcements

  • Reminder: Next Wednesday’s class is Test 1!

    • Contents: Git, Terminal, Markdown, General installation info

• 1st hour - Introduction to Python

  • Announcements (2 mins)

  • Introduction (3 mins)

  • Writing and Running Code (15 min)

  • Interpreting Code (15 min)

  • Review and Recap (5 min)

• Digging Deeper into Python syntax

  • Basic datatypes (15 min)

  • Lists and tuples (15 min)

  • String methods (5 min)

  • Dictionaries (10 min)

  • Conditionals (10 min)

Learning Objectives

• Look at some lines of code and predict what the output will be.

• Convert an English sentence into code.

• Recognize the order specific lines of code need to be run to get the desired output.

• Imagine how programming can be useful to your life!

Part 1: Introduction (5 mins)

Note: Some images may look slightly different than yours as the software gets more polished and icons/user interfaces change, but this should give you a general gist of the essential things.

Useful things to know about JupyterLab

• Open JupyterLab

• Create new notebooks

• Entering and exiting “Command mode”

• Converting cells to “markdown format”

• Using JupyterLab for Markdown files

• Close JupyterLab

Part 2: Writing and Running code (15 mins)

Using Python to do Math

Task	Symbol
Addition	+
Subtraction	-
Multiplication	*
Division	/
Square, cube, …	**
Squareroot, Cuberoot, …	**
Trigonometry (sin,cos,tan)	Later…

Demo (side-by-side)

Addition

4 + 5 + 2

11

# Subtraction

4 - 5

-1

# Multiplication
4 * 5

20

# Division

11 / 2

5.5

# Square, cube, ...

2**4

16

# Squareroot, Cuberoot, ...

27 ** (1 / 3)

3.0

Assigning numbers to variables

• You can assign numbers to a “variable”.

• You can think of a variable as a “container” that represents what you assigned to it

• There are some rules about “valid” names for variables, we’ll talk about the details later

  • Rule 1: Can’t start the name of a variable with a number!

• General guideline for now: just use a combination of words and numbers

Demo (side-by-side)

# Two numbers

num1 = 40
num2 = 12

print(num1, num2)

40 12

# Multiply numbers together

num1 * num2

480

Assigning words to variables

• You can also assign words and sentences to variables!

• Surround anything that’s not a number with double quotes ” and “

mysentence = (
    "This is a whole sentence with a list of sports, swimming, tennis, badminton"
)

print(mysentence)

This is a whole sentence with a list of sports, swimming, tennis, badminton

Using Python to work with words

Python has some nifty “functions” to work with words and sentences.

Here’s a table summarizing some interesting ones, we’ll keep adding to this as the term goes on.

Task	Function
Make everything upper-case	upper()
Make everything lower-case	lower()
Capitalize first letter of every word	title()
Count letters or sequences	count()

Demo (side-by-side)

mysentence

'This is a whole sentence with a list of sports, swimming, tennis, badminton'

# make lower case

mysentence.lower()

'this is a whole sentence with a list of sports, swimming, tennis, badminton'

# make upper case

mysentence.upper()

'THIS IS A WHOLE SENTENCE WITH A LIST OF SPORTS, SWIMMING, TENNIS, BADMINTON'

# split on a comma

mysentence.split(",")

['This is a whole sentence with a list of sports',
 ' swimming',
 ' tennis',
 ' badminton']

mysentence.title()

'This Is A Whole Sentence With A List Of Sports, Swimming, Tennis, Badminton'

mysentence.upper().lower().upper().lower()

'this is a whole sentence with a list of sports, swimming, tennis, badminton'

# count the times "i" occurs
mysentence.count("with")

1

# count two characters: hi
mysentence.count("hi")

1

mysentence2 = "     Hello.     World .....     "
mysentence2

'     Hello.     World .....     '

mysentence2.strip(" ")

'Hello.     World .....'

mysentence2.replace(" ", "^")

'^^^^^Hello.^^^^^World^.....^^^^^'

## RISE settings

from IPython.display import IFrame

from traitlets.config.manager import BaseJSONConfigManager
from pathlib import Path

path = Path.home() / ".jupyter" / "nbconfig"
cm = BaseJSONConfigManager(config_dir=str(path))
tmp = cm.update(
    "rise",
    {
        "theme": "sky",  # blood is dark, nice
        "transition": "fade",
        "start_slideshow_at": "selected",
        "autolaunch": False,
        "width": "100%",
        "height": "100%",
        "header": "",
        "footer": "",
        "scroll": True,
        "enable_chalkboard": True,
        "slideNumber": True,
        "center": False,
        "controlsLayout": "edges",
        "slideNumber": True,
        "hash": True,
    },
)