A Python function is a reusable chunk that can be called to perform a specific task, and it allows us to encapsulate a chunk together and call it multiple times when needed. Exclusive incentives for premium creators
This article will provide a comprehensive introduction to how to call functions in Python, including function definitions, parameter passing, default parameters, and variadics, etc., and help readers better understand them.
Basic calls. In Python, to call a function, you first need to define the function.
The definition of a function typically includes the function name, a list of parameters, and a function body.
Function calls are called with parentheses around the function name, and the parameters passed to the function are placed in the parentheses.
Here's a simple example:
def greet(name):(tab)print(f"hello, !")
The function is called as follows:
greet("alice"Output: Hello, Alice!
In this example, we define a function called greet, which takes a parameter name.
In the body of the function, we use the print statement to output a greeting. We then do this by calling greet("alice") to execute this function and pass the string"alice"as a parameter.
Parameter passing. In Python, there are two ways to pass function arguments: by value and by reference.
By default, parameter passing is per-value, i.e., the function receives a copy of the parameter value, not the parameter itself.
This means that changes to the parameters inside the function do not affect the original values. If you want to pass arguments by reference, you can use a soft object, such as a list or dictionary, as a parameter.
Here's an example of pass-by-value:
def add(a, b):(tab)return a + b
Call the function. result = add(3, 5) return value: 8
In this example, we define a function called add, which takes two arguments, a and b.
In the function body, we return the sum of these two parameters. Since arguments are passed on a per-value basis, changes made inside the function do not affect the original value.
Default and variadic parameters.
In addition to basic data types, such as integers, floats, and strings, you can extend the flexibility of your function with default and variable parameters.
A default parameter can specify a default value when defining a function, so that if the parameter is not provided when the function is called, the default value will be used. Variadics allow any number of arguments to be passed in when a function is called.
Here's an example of using default and variadic parameters:
def greet_multiple(name, others=none, separator=" "):(tab)if others is none:(2tab)others = tab)print(f"hello, !")
Call the function.
greet_multiple("bob"Output: hello, bob!greet_multiple("charlie", ["alice", "d**id"], ", "Output: Hello, Charlie! alice, d**id
In this example, we define a function called greet multiple, which takes three parameters: name, others, and separator.
The others parameter has a default value of none, which means that if the parameter is not provided, it will be assigned as an empty list. The separator parameter is a variable parameter that allows us to pass in a delimiter string when calling a function.
In the body of the function, we check if the others parameter is none, and if it is, replace it with an empty list. Then we use separatorjoin(others) concatenate other people's names into a string and output a greeting.
Summary. In python programming practice, the flexible use of functions can greatly improve the reusability and maintainability of the company.
Through reasonable function division and parameter design, it can be better organized and managed, making it clearer and easier to understand.