What is a Python lambda function?

What is a Python lambda function?

• A. A lambda is a named function defined with the def keyword.
• B. An anonymous, single-expression function defined inline using the lambda keyword.
• C. A class constructor.
• D. A loop construct.

Answer: (B)

A Python lambda function is an anonymous, inline function defined with the lambda keyword, and it must be a single expression. This makes it ideal for small, quick computations you want to pass directly to another function or assign to a variable. Because it’s anonymous and defined in one line, it’s different from a regular function created with def, which produces a named function and can contain multiple statements. A lambda’s body is just an expression, and its value is the result of that expression. For example, you can do f = lambda x, y: x + y, and f(2, 3) returns 5. Lambdas are not class constructors and not loop constructs; they’re simply compact functions used where a short, on-the-fly function is convenient, such as in map, filter, or sort with a key.

A Python lambda function is an anonymous, inline function defined with the lambda keyword, and it must be a single expression. This makes it ideal for small, quick computations you want to pass directly to another function or assign to a variable.

Because it’s anonymous and defined in one line, it’s different from a regular function created with def, which produces a named function and can contain multiple statements. A lambda’s body is just an expression, and its value is the result of that expression. For example, you can do f = lambda x, y: x + y, and f(2, 3) returns 5.

Lambdas are not class constructors and not loop constructs; they’re simply compact functions used where a short, on-the-fly function is convenient, such as in map, filter, or sort with a key.