How can I implement a multi dimensional array or array of records in Python?
Question:
I’ve learned the theory in a computer science class about multi dimensional arrays & records of arrays but I am unsure of how to implement this in Python. I was thinking of using an array of records as it would allow me to have different data types in the one record but at the same time I was thinking that a multi dimensional array would also be good to learn in Python.
I’ve Googled around a bit & I have found numpy but I’m not sure which function in numpy I’d use. I saw one with tuples but I wasn’t keen on using that as tuples can’t be modified.
I’m using Python 3.2 but I don’t mind using Python 2.7 either.
Answers:
Depends how you want to interact with them. Consider using Numpy. Specifically, have a look at the N-Dimensional array. It provides a rich API for manipulation and comparison.
If numpy feels like overkill, you can implement a multi-array using simple tuples/lists.
multi_array = [
[1, 2, 3, 4, 5],
[6, 7, 8, 9, 10]
]
>>> multi_array[0][0]
>>> multi_array[1][4]
As an example, to convert multi_array into a numpy ndarray:
import numpy as np
np.ndarray((2, 5), buffer=np.array(multi_array), dtype=int)
Notice that ndarray expects as it’s first argument a shape. This means you need to know the dimensions of the array before you create it. Changing the dimensions of the ndarray is known as ‘reshaping’.
not sure what you mean by “records” but you could use a list of lists to represent a two dimensional array. read the docs to find out more.
I’ve learned the theory in a computer science class about multi dimensional arrays & records of arrays but I am unsure of how to implement this in Python. I was thinking of using an array of records as it would allow me to have different data types in the one record but at the same time I was thinking that a multi dimensional array would also be good to learn in Python.
I’ve Googled around a bit & I have found numpy but I’m not sure which function in numpy I’d use. I saw one with tuples but I wasn’t keen on using that as tuples can’t be modified.
I’m using Python 3.2 but I don’t mind using Python 2.7 either.
Depends how you want to interact with them. Consider using Numpy. Specifically, have a look at the N-Dimensional array. It provides a rich API for manipulation and comparison.
If numpy feels like overkill, you can implement a multi-array using simple tuples/lists.
multi_array = [
[1, 2, 3, 4, 5],
[6, 7, 8, 9, 10]
]
>>> multi_array[0][0]
>>> multi_array[1][4]
As an example, to convert multi_array into a numpy ndarray:
import numpy as np
np.ndarray((2, 5), buffer=np.array(multi_array), dtype=int)
Notice that ndarray expects as it’s first argument a shape. This means you need to know the dimensions of the array before you create it. Changing the dimensions of the ndarray is known as ‘reshaping’.
not sure what you mean by “records” but you could use a list of lists to represent a two dimensional array. read the docs to find out more.