Learn about Dictionary and start with Pandas

Long time no see,

In this session, we will walk you through through a learning session of how to use dictionary and get started with pandas, one of the most popular open-source library in python.

Before jumping into content, we would like to thank Eric Matthews for his amazing book "Python Crash Course: A Hands-on, Project-based Introduction to Programming" Again, feel free to ask if you have any question.

Outline

• What is Dictionary
  • Accessing values
  • Adding/ Removing new key-value pairs
  • Starting with values in a Dictionary
• How to work with Dictionary
  • Looping
    • Loop through all key-value pairs
    • Loop through all the keys in a Dictionary
    • Loop through all a Dictionary's keys in order
    • Loop through all values in a Dictionary
  • Nesting
    • A list of Dictionary
    • A list of a Dictionary
    • A Dictionary in a Dictionary

What is a Dictionary?

Let us take a simple to explain what Dictionary or Dict is

"""
Example of a Dictionary with a variable named `workshop_attendee`.
"""
workshop_attendee = {"Name": ["Alice", "Bob", "Chris"], "Occupation": ["student", "marketer", "researcher"], "Age": [20, 27, 35]}

print(workshop_attendee)

In simple words, we would say Dict is a data structure allowing us to

How to access values

print(workshop_attendee["student"])
print(workshop_attendee["student"][0])

# Return an object Dictionary_values, e.g. dict_values([key1, key2])
workshop_attendee.values()

# Return an object of Dictionary keys, e.g. dict_keys([key1, key2])
workshop_attendee.keys()

# Return an object of Dictionary item, e.g. dict_items([(key1, value1), (key2, value2)])
workshop_attendee.items()

** Why dict_items, dict_values, dict_values? **

How to add/ remove new key-value pairs

workshop_attendee["Year of Experience"] = "Less than a year" #Add a value.
print(workshop_attendee)

del workshop_attendee["Year of Experience"] #Remove keys and values.
print(workshop_attendee)

How to work with Dictionary

for key, value in workshop_attendee.items():
  print("\n Key %s" % key)
  print("\n Value %s" % value)