Grid Reference

The byugrid library helps you learn to program by using a 2-dimensional grid. You can think of the grid as a set of cells, indexed by x values along the horizontal axis (left to right) and y values along the vertical axis (top to bottom).

Each cell can hold an arbitrary value, such as an integer or a string.

Installing the grid library

The most reliable way to install byugrid is through PyCharm. Open the File->Settings (Windows) or File->Preferences (MacOS) menu and select Project. You should see a your Conda environment and a list of packages installed in that environment:

Click the + and then type in byugrid. Then click Install Package.

Alternatively, you can type pip install byugrid in a PyCharm terminal. Be sure that terminal is using the CS 110 environment.

Importing the grid library

To use the Grid, you always need to import it using the following:

from byugrid import Grid

Creating a grid

You can create a grid in two ways:

• Grid(width, height) — creates a new grid whose size is given by width and height (width specifies columns and height specifies rows)

• Grid.build(rows) — creates a new grid using the supplied rows.

In the first case, we can create a blank grid:

grid = Grid(3, 2)

This creates a new Grid, like the one shown above, that is 3 columns wide and 2 rows high. The value of each cell is None. The world is stored in a variable called grid.

In the second case, we can create a grid by specifying every value:

grid = Grid.build([[None, None, 'a'], [None, None, 'b']])

This creates a grid that looks like this:

Grid height and width

You can get the grid width and height using the following:

• grid.width — grid width in cells
• grid.height — grid height in cells

You can use these to loop over the rows and columns. For example:

# loop over all the columns
for x in range(grid.width)

# loop over all the rows
for y in range(grid.height)

Getting and setting cell contents

You can get and set cell contents using the following:

• grid.get(x, y) — get the contents of the cell at coordinate (x, y)
• grid.set(x, y, value) — set the contents of the cell at coordinate (x, y) to contain the supplied value

For example:

# gets the value at (1, 2)
value = grid.get(1, 2)

# sets the value at (3, 4) to contain 'hello'
grid.set(3, 4, 'hello')

Checking if a coordinate is in bounds

If you try to get or set a coordinate that is not in bounds, you will cause a Python error. Before getting or setting a coordinate, you can check if it is in bounds using:

• grid.in_bounds(x, y) — returns True if the coordinate is in bounds, False otherwise

Cheat Sheat

from byugrid import Grid

• Create
  • Grid(width, height) — creates a new, blank grid
  • Grid.build(rows) — creates a new grid using the supplied rows, e.g. Grid.build([[None, None, 'a'], [None, None, 'b']])
• Width and height
  • grid.width — grid width in cells
  • grid.height — grid height in cells
• Looping over pixels
  • for x in range(grid.width): — loop over all columns
  • for y range(grid.height): — loop over all rows
• Getting and setting cell contents
  • grid.get(x, y) — get the contents of the cell at coordinate (x, y)
  • grid.set(x, y, value) — set the contents of the cell at coordinate (x, y) to contain the supplied value
• Bounds checking
  • grid.in_bounds(x, y) — returns True if the coordinate is in bounds, False otherwise