Python's Pocket Oxford

Welcome back to Pandas Daily! Your daily 5-minute boost to becoming confident in Python.

Today: Let’s dive into Python "Dictionaries", the toolbox for storing data with labels and values.

If you are an absolute beginner you can glance through previous issues as well

Think of Python Dictionaries like a real world dictionary: you look up a word (key) and find its meaning (value). Data is basically stored as key-value pair. Use when you want to connect a label (like a name) to information (like a score, age, etc.).

🚀 Create a dictionary and explore its elements/items

Cat, Dog are keys (animal). Meow, Bark are values (sounds)

  In [1]:
  my_dict = {
  "cat": "meow", 
  "dog": "bark"
  }

  print(my_dict)

  Out [1]: {'cat': 'meow', 'dog': 'bark'}

💳 Access value (bark) using the key (dog)

  In [2]:
  print(my_dict["dog"])

  Out [2]: bark

Change value (meow ➡️ purr) of a key

  In [3]:
  my_dict["cat"] = "purr"

  print(my_dict)

  Out [3]: {'cat': 'purr', 'dog': 'bark'}

✅ Super easy to add a new key value pair

  In [4]:
  # Add a new key-value pair

  my_dict["cow"] = "moo"

  print(my_dict)

  Out [4]: {'cat': 'purr', 'dog': 'bark', 'cow': 'moo'}

Likewise super easy to delete ❌ key value pair

  In [5]:
  del my_dict["cow"]

  print(my_dict)

  Out [5]: {'cat': 'purr', 'dog': 'bark'}

🧠 To get keys, values or all items ➡️ use "list", yes the one we went through yesterday

  In [6]:
  # This was not the output we needed

  my_dict.keys

  Out [6]:  

  In [7]:
  print(list(my_dict.keys()))

  Out [7]: ['cat', 'dog']

  In [8]:
  print(list(my_dict.values()))

  Out [8]: ['purr', 'bark']

  In [9]:
  print(list(my_dict.items()))

  Out [9]: [('cat', 'purr'), ('dog', 'bark')]

💡 To access values, you can also use "get" function. But why? You'll know

  In [10]:
  print(my_dict.get("cat"))

  Out [10]: purr

❌🛡️ "lion" is not a key, so traditional access method will throw error which can be avoided using "get"

  In [11]:
  print(my_dict["lion"])

  KeyError: 'lion'

  In [12]:
  print(my_dict.get("lion"))

  Out [12]: None

🦒 Length of dictionary is number of keys (or values)

  In [13]:
  print(len(my_dict))

  Out [13]: 2

❓Quiz time: What do we use to confirm the datatype

  In [14]:
  print(type(my_dict))

  Out [14]: 

🗑️ Empty everything from the dictionary

  In [15]:
  my_dict.clear()

  print(my_dict)

  Out [15]: {}

🚀 💪 Mega "list" containing multiple dictionaries

  In [16]:
  people = [

      {"name": "Mike", "age": 15},

      {"name": "Sarah", "age": 21}

  ]

  print(people)

  Out [16]: [{'name': 'Mike', 'age': 15}, {'name': 'Sarah', 'age': 21}]

🪐🚨Lets print everything together. Also see which datatype is for what!!

  In [17]:

  print(people)

  print(type(people))

  print(people[0])

  print(type(people[0]))

Out [17]:
[{'name': 'Mike', 'age': 15}, {'name': 'Sarah', 'age': 21}]

{'name': 'Mike', 'age': 15}

🎺🎺 Its a wrap for today’s Python adventure—go ahead and play with what you’ve learned! Have a fantastic weekend!

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