python101_workshop_script.py

# Python 101 — In-class Practice Script

# You do NOT need to type everything from scratch.
# Run selected lines and edit values where you see TODO / EXERCISE.

# Tip: You don't need to memorize syntax 
# Focus on patterns and practice by editing values and re-running code.

# ============================================================
# Core basics: variables, comments, print(), type()
# ============================================================

# A '#' starts a comment. Python ignores comments.

text = "foo"        # TODO: change this string
number = 42         # TODO: change this number
pi_value = 3.1415   # TODO: change this value

print("text =", text)
print("number =", number)
print("pi_value =", pi_value)

print("type(text)     ->", type(text))
print("type(number)   ->", type(number))
print("type(pi_value) ->", type(pi_value))

# Numbers vs strings
print(type(10))
print(type(10.0))
print(type("10.0"))

# Operators
print(6 * 7)
print(2 ** 4)
print(13 % 5)
print(3 > 4)
print(True and True)
print(True or False)
print(True == False)


# ============================================================
# EXERCISE 1: Operators
# ============================================================
# TODO:
# 1) Change x and y
# 2) Predict the output
# 3) Re-run this block

x = 13
y = 5

print(x + y)
print(x - y)
print(x * y)
print(x / y)
print(x % y)
print(x ** y)

# ============================================================
# Lists, indexing, slicing, append
# ============================================================

numbers = [1, 2, 3]          # TODO: change list values
print(numbers)
print(numbers[0])
print(numbers[-1])

# Loop through a list
for n in numbers:
    print(n)

# Slicing
a = [1, 2, 3, 4, 5]
print(a[1:3])
print(a[:2])
print(a[2:])

# Append (a list method)
numbers.append(4)            # TODO: append something else
print(numbers)

# ============================================================
# EXERCISE 2: Lists
# ============================================================
# TODO:
# 1) Change my_list
# 2) Change slicing range
# 3) Append a STRING

my_list = [10, 20, 30, 40, 50]
print(my_list)

start = 1
end = 4
print(my_list[start:end])

my_list.append("NEW")
print(my_list)

# ============================================================
# Loops, tuples, dictionaries
# ============================================================

values = ["foo", "bar", "baz"]
for val in values:
    print(val)

# enumerate gives index + value
for idx, val in enumerate(values):
    print(idx, val)
    print(str(idx)+"="+val)

# Tuples (immutable)
a_tuple = (1, 2, 3)
another_tuple = ("blue", "green", "red")
print(a_tuple[0])
print(another_tuple.index("green"))

# Dictionaries
translation = {"one": "first", "two": "second"}
print(translation['one'])


for key, value in translation.items():
    print(key, value)
    
for key in translation.keys():
    print(key, '->', translation[key])


# ============================================================
# EXERCISE 3: Object types
# ============================================================
# TODO:
# 1) Create a list OR tuple OR dictionary
# 2) Print the first element/value
# 3) Loop through it

ex_list = [1, 2, 3]          # TODO: edit or replace
print(ex_list[0])

for item in ex_list:
    print(item)

# ============================================================
# Functions and help()
# ============================================================

def add_function(a, b):
    """Return the sum of a and b."""
    return a + b


print(add_function(5, 10))

# TODO (optional):
# Try changing the function body or inputs above.
# Try help(add_function)

# ============================================================
# Conditionals: if / elif / else
# ============================================================

a = 5

if a == 5:
	print('A equals 5')


a = 6
if a == 5:
	print('A equals 5')
else:
	print('A is not equal to 5')



a = 'foo'
b = 'bar'

if a == 'foo':
    if b == 'bar':
        print('OK this is cool!')
    else:
        print('All foo no bar')



a = 7
if a > 5 and a < 10:
	print('A is between 5 and 10')

a = 15
b = 5
c = 20


if a > b or a < c:
	print(f'A is between {b} and {c}')
    
    

a = 5
b = 10
if not a > b:
	print('A is not greater than B')
    

# ============================================================
# EXERCISE 4: Conditions
# ============================================================
# TODO:
# 1) Change a to 3
# 2) Change score to 60
# 3) Predict what will print, then re-run

a = 7
if a > 5 and a < 10:
    print("A is between 5 and 10")
else:
    print("A is NOT between 5 and 10")

score = 93
if score >= 90:
    print("grade: A")
elif score >= 80:
    print("grade: B")
else:
    print("grade: C or below")

# ============================================================
# Shorthanded methods 
# ============================================================

a = 5
if a != 10: print('A is not 10')

# TODO:
# Change the value of a to 10.
# What happens? Why?


a = 5
b = 10
print('A') if not a < b else print('B')	

# TODO:
# Try changing a and b.
# Example:
# a = 20, b = 10
# a = 5,  b = 3
# Before running, predict which letter will be printed.

# ============================================================
# Nested, breaking and shorthanding loops
# ============================================================

for i in range(4):
    print('\n')
    for j in range(3):
        print(f'i = {i}    j = {j}')
        
# TODO:
# Change range(4) or range(3) to a different number.
# How does the output change?


states = ['Colorado', 'Florida', 'Hawaii', 'California', 'Alaska'] 
for state in states:
    if state == 'Colorado':
        break
    print(state)
    
# TODO:
# Move 'Colorado' to a different position in the list.
# What gets printed now?
# What happens if you remove the 'break' line?


mylist = [1, 'One', 'Two', 2, 'three', 3.14]
[print(x) for x in mylist]

# TODO:
# Replace print(x) with type(x).
# What do you notice about the different elements?