Array Reshaping
Reshaping allows you to change the shape of an array without altering the data. Below is an example demonstrating how to reshape a NumPy array:
import numpy as np arr = np.arange(12) # Create an array with 12 elements reshaped_arr = arr.reshape(3, 4) # Reshape it into a 3x4 matrix print("Original Array:", arr) print("Reshaped Array:\n", reshaped_arr)
Tip: Use
-1
to automatically infer one dimension. auto_reshaped = arr.reshape(4, -1) # NumPy automatically calculates the missing dimension print(auto_reshaped.shape) # Output: (4, 3)
Array Iteration
Iterating over arrays is a fundamental operation in NumPy. You can iterate over 1D and 2D arrays efficiently:
1. Iterating Over a 1D Array
arr_1d = np.array([10, 20, 30, 40]) for num in arr_1d: print(num)
2. Iterating Over a 2D Array
You can iterate over a 2D array row by row or element by element using np.nditer()
:
arr_2d = np.array([[1, 2, 3], [4, 5, 6]]) # Iterating row by row for row in arr_2d: print("Row:", row) # Iterating element by element for element in np.nditer(arr_2d): print("Element:", element)