NumPy ndarray.data Attribute

NumPy ndarray.data

The ndarray.data attribute provides a Python buffer object pointing to the start of the array’s data. This attribute allows direct access to the underlying memory of the array.

Syntax

ndarray.data

Attributes

Attribute	Type	Description
data	buffer object	A buffer object pointing to the start of the array’s data in memory.

Return Value

Returns a Python buffer object that points to the start of the array’s memory.

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Examples

1. Accessing the Data Buffer of an ndarray

In this example, we create a NumPy array and access its data attribute to obtain the memory buffer.

import numpy as np

# Create a NumPy array
arr = np.array([1, 2, 3, 4, 5], dtype=np.int32)

# Access the data buffer of the array
buffer = arr.data

# Print the memory address of the buffer
print("Memory address of data buffer:", buffer)

Output:

Memory address of data buffer: <memory at 0x7f6303904940>

The output shows the memory location of the buffer where the array’s data is stored.

2. Using ndarray.data to View the Memory Contents

Here, we access the raw memory content of the array using the tobytes() method.

import numpy as np

# Create a NumPy array
arr = np.array([10, 20, 30, 40], dtype=np.int16)

# Access the data buffer
buffer = arr.data

# Convert the buffer to bytes to inspect raw memory content
raw_data = arr.tobytes()

# Print the memory buffer and raw data
print("Memory buffer address:", buffer)
print("Raw memory data:", raw_data)

Output:

Memory buffer address: <memory at 0x7f8b16400940>
Raw memory data: b'\n\x00\x14\x00\x1e\x00(\x00'

The raw data is displayed as bytes, representing the integer values stored in memory.

3. Checking If Two Arrays Share the Same Memory Buffer

In this example, we check whether two different arrays share the same data buffer.

import numpy as np

# Create an initial NumPy array
arr1 = np.array([5, 10, 15, 20], dtype=np.int32)

# Create a view of the array
arr2 = arr1.view()

# Check if both arrays share the same memory buffer
same_buffer = arr1.data == arr2.data

# Print memory addresses and buffer comparison
print("Memory buffer address of arr1:", arr1.data)
print("Memory buffer address of arr2:", arr2.data)
print("Do arr1 and arr2 share the same memory buffer?", same_buffer)

Output:

Memory buffer address of arr1: <memory at 0x7f372fc00a00>
Memory buffer address of arr2: <memory at 0x7f372fc00a00>
Do arr1 and arr2 share the same memory buffer? True

Since arr2 is a view of arr1, both arrays share the same memory buffer.