How to use lambda functions in Python?

1 year ago
Noah Thompson
1 minute

In Python, a lambda function is an anonymous function that can be used anywhere a function object is required. The syntax of a lambda function is as follows:

lambda arguments: expression

A lambda function consists of the following parts:

  1. Lambda keyword: used to indicate that this is a lambda function.
  2. Arguments are the parameters of a function, and there can be multiple parameters separated by commas.
  3. : This is used to separate parameters and expressions.
  4. The expression represents the return value of the function, which is the function body.

Here are a few examples of using lambda functions.

  1. Calculate the sum of two numbers:
add = lambda x, y: x + y
result = add(3, 4)
print(result)  # 输出：7
  1. Determine if a number is odd or even:
is_odd = lambda x: x % 2 != 0
result = is_odd(5)
print(result)  # 输出：True
  1. Sort a list.
numbers = [4, 2, 7, 1, 5]
sorted_numbers = sorted(numbers, key=lambda x: x)
print(sorted_numbers)  # 输出：[1, 2, 4, 5, 7]

In the above examples, lambda functions can be used directly in assignment statements or as arguments for other functions. However, it is important to note that lambda functions are typically used for simple function logic. For more complex functions, it is recommended to use regular function definitions instead.

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