# 字典推导式

代码：

```python
mcase={'a':10,'b':34,'A':7,'Z':3}

print('mcase:',mcase)
print()
print('忽略key大小写，相加key的value，且过滤掉不是a,b的')
mcase_frequency={
    k.lower():mcase.get(k.lower(),0)+mcase.get(k.lower(),0)
    for k in mcase.keys()
    if k.lower() in ['a','b']
}

print('mcase_frequency:',mcase_frequency)
print()
print('反转mcase的 k,v')
mcase_revers={v:k for k,v in mcase.items()}
print(mcase_revers)
```

结果：

```python
mcase: {'a': 10, 'b': 34, 'A': 7, 'Z': 3}

忽略key大小写，相加key的value，且过滤掉不是a,b的
mcase_frequency: {'a': 20, 'b': 68}

反转mcase的 k,v
{10: 'a', 34: 'b', 7: 'A', 3: 'Z'}
```

视频：

```
wait
```


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