from itertools import groupby

# Sample data (must be sorted by the key you want to group by)
data = [
    {'name': 'Alice', 'city': 'New York'},
    {'name': 'Bob', 'city': 'London'},
    {'name': 'Charlie', 'city': 'New York'},
    {'name': 'David', 'city': 'London'},
    {'name': 'Eve', 'city': 'Paris'}
]

# Sort the data by 'city' for groupby to work correctly
data.sort(key=lambda x: x['city'])
print(f"Sorted data: {data}
")

grouped_by_city = {}
for city, group in groupby(data, key=lambda x: x['city']):
    grouped_by_city[city] = list(group) # Convert group iterator to a list

print(f"Grouped by city: {grouped_by_city}")

# Example of printing groups more clearly
print("
--- Grouped Output ---")
for city, group_items in grouped_by_city.items():
    print(f"City: {city}")
    for item in group_items:
        print(f"  - {item['name']}")