The code and notes from today’s Programming the Pi Session.
Covers an introduction to data types and some of the things we can do with them.
(Note: you can get a sneak peak at part 2 here)
# Variables
# Assigment Operators
x = 1
print(x)
x += 1
print(x)
# x += 1 is equivalent to x = x + 1
# You can use any of the Arithmetic operators in this way
# Types
# =====
# Integers
x = 5
y = 2000
z = -123
# Floats
r = 0.5
t = 3.14159265359
s = -2.567
'''
--------------------
Arithmetic Operators
--------------------
+ (addition)
- (subtraction)
* (multiplication)
/ (division)
% (modulus aka remainder)
** (exponent aka powers )
// (floor division aka rounded down)
'''
z = x * y
print(z)
# Strings
myString = 'Hello World'
print(myString)
# len() gets the length of the string
print(len(myString))
print(myString[1])
print(myString[0])
# we can use ranges
print(myString[0:5])
# no second number runs to the end of the range
print(myString[5:])
# Lists
numbers = [1, 2, 3, 4, 5]
# we can get the number of items in a list with len()
print(len(numbers))
print(numbers)
#You can pull out a specific list item by index
print(numbers[0])
# We can overide list values by index
numbers[0] = 0
print(numbers)
moreNumbers = [6, 7, 8, 9, 10]
# use + to join two lists
allNumbers = numbers + moreNumbers
print(allNumbers)
allNumbers.sort()
print(allNumbers)
allNumbers.reverse()
print(allNumbers)
writtenNumbers = ['One', 'Two', 'Three', 'Four', 'Five']
print(writtenNumbers)
writtenNumbers.sort()
print(writtenNumbers)
# Dictionaries
# Key Value data type
faveColours = {'Rob': 'Blue', 'Dave': 'Red', 'Jane': 'Orange'}
print(faveColours)
print(faveColours['Rob'])
faveColours['Rob'] = 'Purple'
print(faveColours['Rob'])
# Tuples
tupleNumbers = 1, 2, 3, 4, 5
print(tupleNumbers)
# tupleNumbers[0] = 0 <<< This WILL ERROR
# Tuples are IMMUTABLE
# Once set they cannot be changed!
# BUT they can be converted into lists!
listNumbers = list(tupleNumbers)
listNumbers[0] = 0
# Nesting Lists, Dictionaries
allRoutes = [1, 4, 5, 7, 15]
# we can nest lists (and Tuples) within dictionaries or other lists
busRoutes = {'Town': allRoutes, 'Trinity': 4, 'Airport': 15}
print(busRoutes)
print (busRoutes['Town'])
print (busRoutes['Airport'])
#we can nest dictionaries within ditionaries
usefulInfo = {'Width': '9 miles', 'Length': '5 miles', 'Buses': busRoutes}
print(usefulInfo)
print(usefulInfo['Buses'])
# And we can pull out nested items using multiple keys:
print(usefulInfo['Buses']['Town'])