# 2.1.4.4.Missing Data

## 刪除Missing Data

* 刪除任何含有的column

```
df.dropna(axis = 1)
```

* 刪除任何含有NaN的row

```
df.dropna()
```

* 刪除NaN數量小於門檻值的row

```
df.dropna(thresh = 2)
```

## 置換Missing Data

* 換掉NaN的值

```
df.fillna(value = 'Fill value')
```

* 將column 'A'中NaN的值換成column 'A'的平均值

```
df['A'].fillna(value = df['A'].mean())
```