Data Type Conversion and Copying Arrays

Every NumPy array has a fixed data type (e.g., int, float, or bool).

You can change an array’s type using .astype().

When copying arrays, it’s crucial to understand the difference between creating a real copy and merely referencing the same data in memory.

Convert an array from one type to another:

Copy
arr = np.array([1.5, 2.8, 3.0])
int_arr = arr.astype(int)

print(int_arr)  # [1 2 3]

This converts float values into integers.

Assigning one array to another does not create a real copy. Both variables point to the same data.

Copy
a = np.array([1, 2, 3])
b = a  # Not a copy!
b[0] = 99

print(a)  # [99 2 3]  original was modified

Use .copy() to create a true copy:

Copy
c = a.copy()
c[0] = 0

print(a)  # Still [99 2 3]

• Use .astype() to change data types (e.g., float to int).
• Use .copy() to create a real copy of an array.
• Without .copy(), both variables refer to the same array in memory.