Python · Theory

Lambda Functions in Python

Theory

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Lambda Functions in Python

lambda is a one-line function without a def name. Shape: lambda x: x * x. Useful as a key= in sorted, or a tiny map/filter. square = lambda n: n * n then square(5) is 25. Keep it tiny. If you need two statements, write a normal def. Complex lambda looks clever and reads badly.

Viva: “anonymous one-line function”. Then sorted(students, key=lambda s: s["marks"]). Prefer def when the logic has a name worth saying out loud.

Lambda Functions in Python — output — 5 then ['Asha', 'Neha', 'Ravi'] (or same lengths stay). add is a tiny function.

Diagram

lambda a, b: a + b
         │ (2, 3)
         ▼
         5

Exam tip

lambda with sorted key idea.

Example

# lambda
add = lambda a, b: a + b
print(add(2, 3))
print(sorted(["Neha", "Asha", "Ravi"], key=lambda s: len(s)))

Lambda Functions in Python — output: 5 then ['Asha', 'Neha', 'Ravi'] (or same lengths stay). add is a tiny function.

Short notes

DefTiny anonymous function.
RuleSingle expression.
Usekey= in sorted.

Python · Theory

Lambda Functions in Python

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Theory

44/268

Lambda Functions in Python

Viva: “anonymous one-line function”. Then sorted(students, key=lambda s: s["marks"]). Prefer def when the logic has a name worth saying out loud.

Lambda Functions in Python — output — 5 then ['Asha', 'Neha', 'Ravi'] (or same lengths stay). add is a tiny function.

Diagram

lambda a, b: a + b
         │ (2, 3)
         ▼
         5

Exam tip

lambda with sorted key idea.

Example

# lambda
add = lambda a, b: a + b
print(add(2, 3))
print(sorted(["Neha", "Asha", "Ravi"], key=lambda s: len(s)))

Lambda Functions in Python — output: 5 then ['Asha', 'Neha', 'Ravi'] (or same lengths stay). add is a tiny function.

Short notes

DefTiny anonymous function.
RuleSingle expression.
Usekey= in sorted.

Lambda Functions in Python

Example

Short notes

Questions

Lambda Functions in Python

Example

Short notes

Questions