Dictionary Methods

d = {"a": 1, "b": 2, "c": 3}

print(len(d))          # 3
print(str(d))           # "{'a': 1, 'b': 2, 'c': 3}"

d2 = d.copy()            # independent shallow copy
d2["d"] = 4
print(d, d2)               # d unaffected: {'a':1,'b':2,'c':3}  {'a':1,...,'d':4}

print(d.get("z", 0))        # 0 (key missing, default returned)

update()

d = {"a": 1, "b": 2}
d.update({"b": 20, "c": 3})   # existing key "b" updated, new key "c" added
print(d)                       # {'a': 1, 'b': 20, 'c': 3}

clear()

d = {"a": 1, "b": 2}
d.clear()
print(d)   # {}

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Difference between List and Dictionary

# List: access by position
fruits = ["apple", "banana", "mango"]
print(fruits[1])            # 'banana'

# Dictionary: access by key -- much faster for lookups
prices = {"apple": 50, "banana": 30, "mango": 80}
print(prices["banana"])      # 30

Use a list when order/position matters and items are homogeneous. Use a dictionary when you need to look up values quickly by a meaningful label (key).