函數(shù)在Python中用於組織可重用代碼以執(zhí)行特定任務(wù)。通過使用def關(guān)鍵字定義函數(shù)，例如def greet(): print("Hello, world!")，可以多次調(diào)用而無需重複編寫相同代碼。參數(shù)使函數(shù)能接收輸入，return語句返回輸出結(jié)果，從而提升靈活性。 Python內(nèi)置函數(shù)如print()可直接使用，但自定義函數(shù)則適用於特定需求，有助於分解複雜任務(wù)、提高代碼可維護性。應(yīng)在代碼重複出現(xiàn)、程序規(guī)模較大或需單獨測試部分邏輯時使用函數(shù)，這不僅減少冗餘，還增強代碼可讀性和協(xié)作效率。

A function in Python is a block of reusable code designed to perform a specific task. Instead of writing the same code over and over, you define a function once and call it whenever you need that task done. Functions help organize your code, make it cleaner, and improve readability.

How to Define a Function

To create a function in Python, you use the def keyword followed by the function name and parentheses. You can also include parameters inside those parentheses if the function needs input values.

Here's a basic example:

 def greet():
    print("Hello, world!")

This defines a function called greet() that prints a message when called. To run it, just use:

 greet()

Some key points:

• The first line ends with a colon :
• The indented block that follows is the function's body
• Indentation matters — everything at the same level under the def line belongs to the function

Why Use Parameters and Return Values?

Functions become more powerful when they accept inputs (parameters) and give back outputs (return values). This makes them flexible and able to handle different data each time they're called.

For example:

 def add(a, b):
    return ab

Now you can call this function with different numbers:

 result = add(3, 5)
print(result) # Output: 8

Why this matters:

• Parameters let you pass values into the function
• return sends a result back after processing
• You can store or use that result elsewhere in your code

You don't have to return just one thing — you can return multiple values as a tuple.

Built-in vs Custom Functions

Python comes with many built-in functions like print() , len() , and range() . These are always available without needing extra setup.

But when you want to do something specific that isn't covered by built-in tools, you write your own function. That's where defining your own logic really shines.

Examples:

• Built-in: print("Hello")
• Custom:

   def say_hello(name):
    print(f"Hello, {name}!")

  Custom functions let you:

  • Break complex tasks into smaller parts
  • Reuse code across different programs
  • Improve maintainability by keeping related logic together

  ---

  When Should You Use Functions?

  Use functions when:

  • You find yourself repeating the same block of code
  • You want to split a big program into manageable pieces
  • You need to test or debug part of your code separately

  They're especially useful for things like:

  • Performing calculations
  • Handling user input/output
  • Processing data structures

  It's not just about avoiding repetition — it's about making your code easier to read, update, and share.

  基本上就這些。

  以上是Python中的功能是什麼的詳細內(nèi)容。更多資訊請關(guān)注PHP中文網(wǎng)其他相關(guān)文章！