Python Dictionary

📚 fun_with_python_dictionaries.md

🐍 Fun with Python Dictionaries! 🧠💥

Welcome to the world of Python Dictionaries – where curly braces {} become treasure chests, and key-value pairs are your loot! ⚔️💰

A Dictionary in Python is like your magical backpack: unordered (so it might take a sec to find stuff), mutable (you can change what’s inside), and indexed (but in a key-unique way).

In short:

🧳 Dictionary = HashTable from Java + Python’s charm + chaos of an unordered sock drawer.

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1. 🧾 Creating the Dictionary

1.1. With Curly Braces – The OG Way

Just slap some key-value pairs inside {} like it’s a grocery list.

# an empty dictionary
Dict = {}

# a dictionary with 3 items
Dict = {
  "Name": "sujit",
  "Age": 30,
  "Blog": "fossguru"
}

print(Dict)

🖨️ Output:

{'Age': 30, 'Name': 'sujit', 'Blog': 'fossguru'}

1.2. Using the dict() Constructor – The Fancy Pants Way

Why just write curly braces when you can summon dictionaries using dict()? 🎩✨

# Creating a Dictionary with dict() method
Dict = dict({1: 'Python', 2: 'Example'})
print(Dict)

# Creating a Dictionary with tuples
Dict = dict([(1, 'Python'), (2, 'Example')])
print(Dict)

# Notice that the keys are not the string literals
Dict = dict(firstName="sujit", lastName="karne", age=30)
print(Dict)

🖨️ Output:

{1: 'Python', 2: 'Example'}
{1: 'Python', 2: 'Example'}
{'firstName': 'sujit', 'lastName': 'karne', 'age': 30}

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2. 🔍 Accessing the Values – Show Me the Loot

Two ways to get to your precious dictionary values:

• Dict[key] – Classic but may scream (KeyError) if key is missing!
• Dict.get(key) – Nicer, calmer, lets you provide a backup value.

Dict = {
  "name":"sujit",
  "blog":"fossguru",
  "age":30
}

print(Dict["name"])
print(Dict.get("age"))

print(Dict.get("country"))
print(Dict.get("country", "India"))

🖨️ Output:

sujit
30
None
India

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3. 🕵️‍♀️ Is That Key Even There?

Before opening a mystery box, make sure it exists. 🧐

3.1. key in Dict

Dict = {
  "name":"sujit",
  "blog":"fossguru",
  "age":30
}

if "name" in Dict:
  print("name is present")
else:
  print("name is not present")

🖨️ Output:

name is present

3.2. key not in Dict

Dict = {
  "name":"sujit",
  "blog":"fossguru",
  "age":30
}

if "country" not in Dict:
  print("country is not present")
else:
  print("country is present")

🖨️ Output:

country is not present

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4. 🛠️ Adding / Updating the Values

New name? Different country? Dictionaries don’t mind your identity crisis.

Dict = {
  "name":"sujit",
  "blog":"fossguru",
  "age":30
}
print(Dict["name"])

# Updating the name
Dict["name"] = "Alex"
print(Dict["name"])

# Updating the name with update() method
Dict.update({"name": "Brian"})
print(Dict["name"])

# Adding a new item - country
Dict.update({"country": "India"})
print(Dict["country"])

🖨️ Output:

sujit
Alex
Brian
India

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5. 💣 Deleting Dictionary Items

5.1. Using del – The Nuclear Option

Dict = {
  "name":"sujit",
  "blog":"fossguru",
  "age":30
}
print(Dict)

# Deleting the name
del Dict["name"]
print(Dict)

# Deleting the dictionary
del Dict
print(Dict)

🖨️ Output:

{'name': 'sujit', 'blog': 'fossguru', 'age': 30}
{'blog': 'fossguru', 'age': 30}

Traceback (most recent call last):
  File "<string>", line 14, in <module>
NameError: name 'Dict' is not defined

5.2. pop() – A Gentle Kick Out

Dict = {
  "name":"sujit",
  "blog":"fossguru",
  "age":30
}
print(Dict)

# Deleting the name
Dict.pop("name")
print(Dict)

🖨️ Output:

{'name': 'sujit', 'blog': 'fossguru', 'age': 30}
{'blog': 'fossguru', 'age': 30}

5.3. clear() – The Clean Slate

Dict = {
  "name":"sujit",
  "blog":"fossguru",
  "age":30
}
print(Dict)

# Clear all the dictionary items
Dict.clear()
print(Dict)

🖨️ Output:

{'name': 'sujit', 'blog': 'fossguru', 'age': 30}
{}

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6. 🔁 Iterating Over Dictionary Items – For Loop Party 🎉

6.1. Classic for Loop

Dict = {
  "name":"sujit",
  "blog":"fossguru",
  "age":30
}

for k in Dict:
  v = Dict[k]
  print("Key :" + k + ", Value: " + str(v))

🖨️ Output:

Key :name, Value: sujit
Key :blog, Value: fossguru
Key :age, Value: 30

6.2. Values Only – values() method

Dict = {
  "name":"sujit",
  "blog":"fossguru"
}

for v in Dict.values():
  print("Value :" + v)

🖨️ Output:

Value :sujit
Value :fossguru

6.3. Full Combo – items() method

Dict = {
  "name":"sujit",
  "blog":"fossguru"
}

for i in Dict.items():
  print(i)
  print("Key :" + i[0] + ", Value: " + i[1])

🖨️ Output:

('name', 'sujit')
Key :name, Value: sujit

('blog', 'fossguru')
Key :blog, Value: fossguru

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7. 🧙‍♂️ Built-in Dictionary Magic Spells (a.k.a. Methods)

Method	Description
clear()	Clears everything. Poof!
copy()	Makes a clone, no evil twin.
fromkeys()	Mass-produce keys with the same value.
get()	Retrieves values gently.
items()	Shows key-value pairs in a tuple outfit.
keys()	Just the keys, please.
pop()	Bye-bye specific key.
popitem()	Bye-bye last item.
setdefault()	Adds key if missing.
update()	Updates or adds stuff.
values()	Just the values, no strings attached.

Examples? Coming right up 🍿:

Dict = {"name":"sujit", "blog":"fossguru"}
Dict.clear()
print(Dict)

{}

Dict = {"name":"sujit", "blog":"fossguru"}
myDict = Dict.copy()
print(myDict)

{'name': 'sujit', 'blog': 'fossguru'}

keys = ('key1', 'key2', 'key3')
value = 0

Dict = dict.fromkeys(keys, value)

print(Dict)

{'key1': 0, 'key2': 0, 'key3': 0}

Dict = {"name":"sujit", "blog":"fossguru"}

print(Dict.get("name"))

sujit

...and so on! You’ve got the power now 🧠⚡

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🎉 Congrats! You're now officially a Python Dictionary Wizard! 🧙‍♀️🐍