Advatages of a Dictionary vs a 2 dimensional list in Python

Advantages of a Dictionary vs  a 2 dimensional list in Python

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1. Clear meaning with keys (readability)

• Dictionary values are accessed using descriptive keys.

• 2D lists rely on index positions, which are harder to remember.

• # Dictionary: student["age"] 
•  # 2D list:     student[1][2]    ### What does this mean?student["age"]

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2. Faster data access

• Dictionaries use hashing, giving near O(1) lookup time.

• 2D lists require searching, which is slower (O(n)).

3. Flexible structure

• Dictionaries allow adding/removing items without breaking structure.

• 2D lists require strict ordering and consistent indexing.

4. No wasted space

• Dictionaries store only existing key-value pairs.

• 2D lists may contain empty or unused positions.

5. Better for real-world data

• Real data is often named, not numbered.

• Dictionaries naturally model objects (users, products, settings).

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Why you can’t simply publish data as a list

You can, but it’s often inefficient and error-prone:

1. No meaning attached to positions

data = ["Alex", 20, "A"]

→ You must remember what each index represents.

2. Fragile to changes

• Adding a new value shifts indexes.

• Existing code may break.

3. Harder to search

• You must loop through lists to find specific data.

• Dictionaries give instant access using keys.

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Feature	Dictionary	2D List
Access	By key	By index
Speed	Very fast	Slower
Readability	High	Low
Flexibility	High	Low

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When a list is better

• Ordered data

• Repeated values

• Index-based processing (loops, matrices)

When a dictionary is better

• Labeled data

• Fast lookup

• Real-world entities

Conclusion:

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Use a dictionary when data has meaning and needs fast access. Use a list when order and repetition matter.