How to convert NumPy ndarray to Python list

How can we convert NumPy ndarray to Python list ?

When we handle array data, We use NumPy.

It is popular. But we don't remember how to convert NumPy ndarray to Python list.

It should be like NumPy(list).

So today I will introduce "How to convert NumPy ndarray to Python list"

Author

Mid-carieer engineer (AI, system). Good at Python and SQL.

How to convert Python list to NumPy ndarray

In order to convert Python list to NumPy ndarray, we can use numpy.array().

Set list as first parameter in numpy.array().

import numpy as np

data_list1 = [
[1,2,3],
[2,3,4],
[3,4,5],
[4,5,6]
]

np_list = np.array(data_list1)
print(np_list)
print(type(np_list))

# [[1 2 3]
#  [2 3 4]
#  [3 4 5]
#  [4 5 6]]
# <class 'numpy.ndarray'>

How to convert NumPy ndarray to Python list

In order to convert NumPy ndarray to Python list, we can use tolist().

You can use tolist() as method of ndarray.

data_list2 = np_list.tolist()
print(data_list2)
print(type(data_list2))

# [[1, 2, 3], [2, 3, 4], [3, 4, 5], [4, 5, 6]]
# <class 'list'>

Conclusion

Today I explained about "How to convert NumPy ndarray to Python list".

In order to convert Python list to NumPy ndarray, we can use numpy.array().

And we can use tolist() to convert NumPy ndarray to Python list.

I don't remember it. So I usually google it.