Deployment Status Apache License Documentation Status Python Online Python version—Jan 27, 2021

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Collections

Collections are groups of items. Python supports several types of collections. Three of the most common are dictionaries, lists and arrays.

Lists

Lists are a collection of items. Lists can be expanded or contracted as needed, and can contain any data type. Lists are most commonly used to store a single column collection of information, however it is possible to nest lists

Arrays

Arrays are similar to lists, however are designed to store a uniform basic data type, such as integers or floating point numbers.

Dictionaries

Dictionaries are key/value pairs of a collection of items. Unlike a list where items can only be accessed by their index or value, dictionaries use keys to identify each item.

Demo: dates

PPT Demonstrations

Challenges time

Check the following script and try to find the mistake:

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# Create a calculator function
# The function should accept three parameters:
# first_number: a numeric value for the math operation
# second_number: a numeric value for the math operation
# operation: the word 'add' or 'subtract'. The default operation is 'add'
# the function should return the result of the two numbers added or subtracted
# based on the value passed in for the operator
#
# Test your function using named notation passing in only the numbers 6 and 4
# Should return 10
#
# Test your function using named notation with the values 6,4, subtract 
# Should return 2
# 
# BONUS: Test your function with the values 6, 4 and divide 
# Have your function return an error message when invalid values are received

solutions:

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# Create a calculator function
# The function should accept three parameters:
# first_number: a numeric value for the math operation
# second_number: a numeric value for the math operation
# operation: the word 'add' or 'subtract'. The default operation is 'add'
# the function should return the result of the two numbers added or subtracted
# based on the value passed in for the operator
#
def calculator(first_number, second_number, operation='ADD'):
    if operation.upper() == 'ADD':
        return(float(first_number) + float(second_number))
    elif operation.upper() =='SUBTRACT':
        return(float(first_number) - float(second_number))
    else:
        return('Invalid operation please specify ADD or SUBTRACT')


# Test your function using named notation passing in only the numbers 6 and 4
# Should return 10

print('Adding 6 + 4 = ' + str(calculator(first_number=6, second_number=4)))
# Test your function using named notation with the values 6,4, subtract 
# Should return 2
#
print('Subtracting 6 - 4 = ' + str(calculator(first_number=6, second_number=4, operation='subtract')))