A2-Examples
Contents
A2-Examples¶
The following is a set of quick examples of the code constructs that we work through in class.
This notebook does not have any explanations - so do check the course Materials for those details.
Defining Variables¶
Basic Types¶
my_int = 1
my_float = 12.2
my_boolean = True
Collection Types¶
my_string = 'abc'
my_list = [1, 2, 3]
my_tuple = (1, 2, 3)
my_dictionary = {'name1' : True, 'name2' : 12}
Operators¶
Mathematical Operators¶
print('Addition: \t', 12 + 3)
print('Subtraction: \t', 12 - 3)
print('Multiplication: ', 12 * 3)
print('Division: \t', 12 / 3)
Addition: 15
Subtraction: 9
Multiplication: 36
Division: 4.0
print('Exponentiation:\t', 2**2)
print('Remainder: \t', 7%2)
Exponentiation: 4
Remainder: 1
Boolean Operators¶
# Boolean `and`
True and True
True
# Boolean `or`
True or False
True
# Boolean `not`
not True
False
Other Operators¶
# String concatenation
print('a' + 'b' + 'c')
abc
Value Comparisons¶
# Equality comparisons
print('Equal: \t', 1 == 1)
print('Unequal:\t', 2 != 1)
Equal: True
Unequal: True
# Magnitude Comparisons
print('Less Than: \t\t\t', 2 < 3)
print('Greater Than: \t\t\t', 4 > 5)
print('Less Than Or Equal to: \t', 2 <= 2)
print('Greater Than Or Equal to: \t', 3 >= 5)
Less Than: True
Greater Than: False
Less Than Or Equal to: True
Greater Than Or Equal to: False
Conditionals¶
first_condition = False
other_condition = True
if first_condition:
print('if condition')
elif other_condition:
print('elif condition')
else:
print('else condition')
elif condition
Loops¶
# While Loop
ind = 0
while ind < 3:
print('Looping!')
ind = ind + 1
Looping!
Looping!
Looping!
# For Loop
list_of_items = [1, 2, 3]
for item in list_of_items:
print(item)
1
2
3
# For Loop using Range
for iteration in range(5):
print(iteration)
0
1
2
3
4
Functions¶
# Defining a function
def function_name(function_input_1, function_input_2):
output = function_input_1 + function_input_2
return output
# Calling a function
answer = function_name(1, 2)
print('Answer:\t', answer)
Answer: 3
# Define a function with default values
def multiply(num1, num2=2):
return num1 * num2
# Calling a function that has default values
print(multiply(2))
print(multiply(2, 3))
4
6
Combining Functions with Control Flow¶
# Defining a Function with a Conditional inside it
def conditional_function(input_boolean):
if input_boolean == True:
output = 'Yay!'
else:
output = 'Nay.'
return output
# Calling our function
returned = conditional_function(True)
print(returned)
Yay!
# Defining a Function with a Loop inside it
def loop_function(my_list):
new_list = []
for item in my_list:
temp = item + 1
new_list.append(temp)
return new_list
# Calling our function
out_list = loop_function([1, 2, 3])
print(out_list)
[2, 3, 4]
# Function with everything
def busy_function(complex_list):
"""This function takes a complex list, and returns the numbers of booleans in the list."""
boolean_counter = 0
for item in complex_list:
if item == True or item == False:
boolean_counter = boolean_counter + 1
return boolean_counter
# Calling our function
busy_function([True, 7.2, 'and', 13, False, '', None, 'word', True])
3
Errors¶
# Raise an error
raise ValueError('The value you gave is no good.')
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-25-3fd7c3ac350e> in <module>()
1 # Raise an error
----> 2 raise ValueError('The value you gave is no good.')
ValueError: The value you gave is no good.
# Try / Except
try:
sum()
except TypeError:
print('Hmm. It seems that did not work.')
Hmm. It seems that did not work.
Classes¶
class Animal():
# Create a class attribute
domain = 'eukaryota'
# Use init to define instance attributes
def __init__(self, sound):
self.sound = sound
# Define a class method
def speak(self):
print(self.sound)
# Create an instance of our class
gary = Animal('woof')
gary.speak()
woof
Class Inheritance¶
class Monkey(Animal):
def __init__(self, sound):
super().__init__(sound)
self.has_hands = True
def check_hands(self):
if self.has_hands:
print('This animal has hands!')
# Create an instance of our derived
jeff = Monkey('Monkey noise.')
jeff.speak()
jeff.check_hands()
Monkey noise.
This animal has hands!