Now that you can create NumPy arrays, the focus shifts to working with the data they contain. This chapter introduces the techniques for accessing and modifying elements within these arrays.

You will learn how to:

• Retrieve individual elements using their index (e.g., array[i] or array[row, col]).
• Extract sub-arrays using slicing notation for both 1D and 2D structures (e.g., array[start:stop:step]).
• Select data based on logical conditions through boolean indexing.
• Access specific, potentially non-contiguous elements using integer arrays, often called fancy indexing.
• Modify values within an array using these selection techniques.

Mastering these indexing and slicing methods is fundamental for effective data manipulation with NumPy.