Looping through elements of a dictionary in Python

Python is a powerful and widely used programming language that offers a range of features, one of which is the ability to work with dictionaries. In Python, dictionaries are extremely useful for storing data that is structured as key-value pairs. However, accessing each element of a dictionary can sometimes be tricky, especially when the dictionary is large or complex. This is where looping through the elements of a dictionary comes in. By using a loop, you can easily traverse and manipulate all elements of a dictionary, regardless of its size or complexity. In this Python tutorial, we will learn how to loop through the elements of a dictionary using various methods and techniques.

Looping through all elements of a dictionary :

• To loop through all key-value pairs of a dictionary we can use the  items()  method.
• The  items()  method returns an object that contains a list of all key-value pairs of the dictionary.
• The key-value pairs are returned as tuples by the  items()  method.
• We can use a for loop with two variables to iterate over this list of key value pairs - 
• The basic syntax of iterating items of dictionary is as follows :

for key, val in d.items():
 	# process key, val
 	

• The name of the variables an be anything - not necessarily key and val.
• Code Sample : 

quantities = {
    "apple": 10,
    "oranges": 20,
    "banana": 25,
    "Mangoes": 35
}

print("Looping through items of dictionary ")
for key, value in quantities.items():
    print(f"Quantity of {key} = {value}",)
    
# Output
# Looping through items of dictionary 
# Quantity of apple = 10
# Quantity of oranges = 20
# Quantity of banana = 25
# Quantity of Mangoes = 35 
   

Looping through all keys of a dictionary :

• To loop through all keys of a dictionary we can use the  keys()  method.
• The  keys()  method returns an object containing a list of all keys of the dictionary.
• We can use a for loop to iterate over this list of keys.
• The basic syntax of iterating keys of dictionary is as follows :

for key in d.keys():
 	# process key
 	

• Note # : iterating through all keys is the default iteration behavior of dictionary. Hence we can iterate over the dictionary directly.
• The  keys()  method comes in handy when we need a list of keys for some reason.
• Code Sample : 

quantities = {
    "apple": 10,
    "oranges": 20,
    "banana": 25,
    "Mangoes": 35
}

print("Looping through items of dictionary ")
for key in quantities.keys():
    print(f"Quantity of {key} = {quantities[key]}")

print()
available_fruits = list(quantities.keys())
print("List of available fruits : ", available_fruits)
    

# Output
# Looping through items of dictionary 
# Quantity of apple = 10
# Quantity of oranges = 20
# Quantity of banana = 25
# Quantity of Mangoes = 35 

# List of available fruits :  ['apple', 'oranges', 'banana', 'Mangoes']

Looping through all values of a dictionary :

• To loop through all values of a dictionary we can use the  values()  method.
• The  values()  method returns an object containing a list of all values of the dictionary.
• We can use a for loop or a while loop to iterate over this list of values. 
• The basic syntax of iterating values of a dictionary is as follows :

for value in d.values():
 	# process value
 	

• Code Sample : 

quantities = {
    "apple": 10,
    "oranges": 20,
    "banana": 25,
    "Mangoes": 35
}

stock = 0
print("Calculating total stock")
for value in quantities.values():
    stock = stock + value

print(f"Total fruits available = {stock}")

# Output
# Calculating total stock
# Total fruits available = 90