A function is the name of a job. When you call the name, that job runs again. You do not copy the same code everywhere. You can pass data in, such as a city name. When the job ends it can return a result, such as the time. A clear name makes the code readable. `hello()` writes the same sentence every time you call it. If you pass a name in, the sentence changes with that name. A function does not run by itself. The line that calls it runs it.

What is a function?

A function is the name of a job. When you call the name, that job runs again. You do not copy the same code everywhere.

You can pass data in, such as a city name.
When the job ends it can return a result, such as the time.
A clear name makes the code readable.

hello() writes the same sentence every time you call it. If you pass a name in, the sentence changes with that name. A function does not run by itself. The line that calls it runs it.

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About this tool

A function is a named block of code that performs a specific task. When you call its name, the code runs again. Functions avoid duplicating the same code throughout your program, keeping it clean and readable.

You can pass data into a function as parameters, allowing the function to behave differently each time. After completing its work, a function can return a result, such as the current time or a calculation outcome.

How to use it

Choose a descriptive name and declare the function using `def` (Python) or `function` (JavaScript).
Write the operations inside the function and use `return` to output a value.
Call the function by its name and provide any required arguments.
Print or log the returned value to see the result.

Common uses

Formatting text for display.
Processing database query results.
Validating user input.
Updating dynamic content on a web page.

Frequently asked questions

What is a function?

A function is a named block of code that performs a specific task.

How do you call a function?

You call it by writing its name and passing any needed arguments, e.g., `myFunc(5)`.

What does a function return?

A function returns a value using `return`, which can then be used by the calling code.