Table widget 中itemAt

In Qt, the `QTableWidget` class provides a method called `itemAt()` which returns a pointer to the item at the given position in the widget's coordinate system. The method takes two integer arguments, `x` and `y`, which represent the horizontal and vertical position of the item.

Here's an example usage of `itemAt()`:

# Assuming that we have a QTableWidget instance called "tableWidget"
item = tableWidget.itemAt(2, 3)  # Returns the item at row 2, column 3
if item is not None:
    print(f"Item text: {item.text()}")
else:
    print("No item found at the given position")

This code snippet retrieves the item at row 2, column 3 of the `tableWidget` instance and prints its text if it exists. If no item is found at the given position, a message is printed indicating so.