生成5个简洁的Python代码片段，用于演示基本的数据处理操作，并且每个片段的长度不超过两行。
user
1. 计算列表中所有元素的和：
```python
numbers = [1, 2, 3, 4, 5]
total = sum(numbers)
```

2. 找出列表中的最大值：
```python
numbers = [10, 20, 30, 40, 50]
max_value = max(numbers)
```

3. 将字符串转换为小写：
```python
text = "Hello World"
lowercase_text = text.lower()
```

4. 过滤列表中的偶数：
```python
numbers = [1, 2, 3, 4, 5]
even_numbers = [num for num in numbers if num % 2 == 0]
```

5. 将字典中的键和值互换：
```python
original_dict = {'a': 1, 'b': 2, 'c': 3}
swapped_dict = {value: key for key, value in original_dict.items()}
```
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