Method:walkGrid

grid walker

travels through the whole dataset executing a callback per each cell

Note: callback functions get the value of the cell as an argument, and whatever that callback returns will be used to replace the current value of that cell.

1. Argument string $callback the callback function to be called per

each cell in the dataset.

• Visibility public
• Returns void
• Also see walkColumn(), walkRow(), fillColumn(), fillRow(), fillCell()