Dictionary Programs

Frequency of User Logins

users = ['john', 'bob', 'alex', 'alice', 'charlie', 'john',
         'alex', 'alice', 'john', 'alex']

logins = {}

for username in users:

    if username in logins:
        logins[username] += 1
    else:
        logins[username] = 1

for user, count in logins.items():
    print(f"{user:8} : {count} logins")

Word Frequency Counter

python

sentence = "apple banana orange apple apple banana grape orange apple"

words = sentence.split()  # Split into a list of words
word_count = {}           # Dictionary to store word counts

for word in words:
    if word in word_count:
        word_count[word] += 1
    else:
        word_count[word] = 1

print("Word Frequency:")
for word, count in word_count.items():
    print(f"{word:8} : {count} times")

Output:

text

Word Frequency:
apple    : 4 times  
banana   : 2 times  
orange   : 2 times  
grape    : 1 times  

Key Similarities to Your Original Program:

1. Uses a list of items (words instead of usernames).
2. Counts occurrences using a dictionary.
3. Prints formatted output.

Example 1: Voting System (Count Votes for Candidates)

python

votes = ["Alice", "Bob", "Alice", "Charlie", "Bob", "Alice", "Alice", "Bob"]

vote_count = {}

for candidate in votes:
    if candidate in vote_count:
        vote_count[candidate] += 1
    else:
        vote_count[candidate] = 1

print("Election Results:")
for candidate, votes in vote_count.items():
    print(f"{candidate:8} : {votes} votes")

Output:

text

Election Results:
Alice    : 4 votes  
Bob      : 3 votes  
Charlie  : 1 votes  

---

Example 2: Product Inventory (Count Items Sold)

python

sales = ["Laptop", "Mouse", "Keyboard", "Laptop", "Mouse", "Monitor", "Laptop"]

inventory = {}

for product in sales:
    if product in inventory:
        inventory[product] += 1
    else:
        inventory[product] = 1

print("Products Sold:")
for product, quantity in inventory.items():
    print(f"{product:8} : {quantity} units")

Output:

text

Products Sold:
Laptop   : 3 units  
Mouse    : 2 units  
Keyboard : 1 units  
Monitor  : 1 units