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# numpy

## ndarray.tolist()

```python
a = np.array([1, 2])
a.tolist()
# [1, 2]

a = np.array([[1, 2], [3, 4]])
list(a)
# [array([1, 2]), array([3, 4])]
a.tolist()
# [[1, 2], [3, 4]]
```

## 平均值

```python
np.mean([1, 2, 3])
# 2.0

np.average([1, 2, 3])
# 2.0
```

參考資料：\
比較差異 - <https://stackoverflow.com/questions/20054243/np-mean-vs-np-average-in-python-numpy>