# lambda表达式

`lambda` 表达式是一行函数。\
它们在其他语言中也被称为匿名函数。如果你不想在程序中对一个函数使用两次，你也许会想用 lambda 表达式，它们和普通的函数完全一样。

**原型**

```python
    lambda 参数:操作(参数)
```

**例子**

```python
    add = lambda x, y: x + y

    print(add(3, 5))
    # Output: 8
```

这还有一些lambda表达式的应用案例，可以在一些特殊情况下使用：

**列表排序**

```python
    a = [(1, 2), (4, 1), (9, 10), (13, -3)]
    a.sort(key=lambda x: x[1])

    print(a)
    # Output: [(13, -3), (4, 1), (1, 2), (9, 10)]
```

**列表并行排序**

```python
    data = zip(list1, list2)
    data = sorted(data)
    list1, list2 = map(lambda t: list(t), zip(*data))
```


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