CODEWITHSUNDEEP
pythonsignature
Hajin Lee
Hajin Lee

Reputation: 169

What is a function signature?

I was studying python and I ran into the concept of 'signature'. I looked things up but signature of a function seems to have different meaning for different languages. So, what does signature of a function refer to in python?

Upvotes: 10

Views: 31651

Answers (3)

casr
casr

Reputation: 100

A function signature is its declaration, parameters, and return type.

def func(params):
    #some stuff
    return modified_params

When you call it is an instance of that function.

var = func(parameters)

Upvotes: 0

dreichler
dreichler

Reputation: 373

In general the signature of a function is defined by the number and type of input arguments the function takes and the type of the result the function returns.

As an example in C++ consider the following function:

int multiply(int x, int y){
    return x*y;
}

The signature of that function, described in an abstract way would be the set {int, int, int}.

As Python is a weakly typed language in general the signature is only given by the amount of parameters. But in newer Python versions type hints were introduced which clarify the signature:

def multiply(x: int, y: int) -> int:
    return x*y

Upvotes: 19

tripleee
tripleee

Reputation: 189457

The signature indicates the names and types of the input arguments, and (with type annotations) the type of the returned result(s) of a function or method.

This is not particular to Python, though the concept is more central in some other languages (like C++, where the same method name can exist with multiple signatures, and the types of the input arguments determine which one will be called).

Upvotes: 4

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