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Python example 'lesson1-Structure'
lesson1-Structure
Python beginners example: lesson1-Structure
# Lists can contain any other data type such as numbers or strings.
numbers = [4, 7, 10, -5, 2]
words = ["fish", "tree", "steel", "compiler"]
# Lists can also contain other lists. We can think of a list-of-lists as a two-
# dimensional list, or grid. Each inner list represents a row in the grid. We
# can even use spaces to line up each inner list in a grid-like way.
grid = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
# All of the normal rules about indexing and slicing still apply.
print("The first numer is {}".format(numbers[0]))
print("The last two words are {}".format(words[-2:]))
print("The grids middle row is {}".format(grid[1]))
print()
# We can access individual items in the grid by first picking out their row
# Then choosing the correct item in that row. Let's pick out the item in
# row 2, column 1. (That's the 8; make sure you know why.)
secondRow = grid[2]
item = secondRow[1]
print("The item at position 2, 1 is {}".format(item))
# Since each row in the table is just a list, we can easily add new rows to
# by creating them as new lists and appending them to an existing table.
newRow = [10, 11, 12]
grid.append(newRow)
# Show the new fourth row in the grid.
#print("The new fourth row is.....
# Adding a column is also possible, but takes a little more work.
# ---------------- Exercises -----------------
# 1. To make sure we successfully added that new row, let's print(it out.)
# Complete (and uncomment) line 36 to show the row was successfully added.
# 2. On lines 24 and 25 I accessed an item in two steps. This is probably the
# clearest way to introduce the material, but in practice it's much more
# common to do that in one step. Replace lines 24 and 25 with a one-liner
# that performs the same task.
# 3. ADVANCED: Adding a row to the grid was relatively easy. Adding a column is
# is also possible, but it means adding an item to each row that is already
# in the grid. Starting around line 40, add a fourth column of all 0s to
# the grid. When you're done the grid should look like this.
# 1 2 3 0
# 4 5 6 0
# 7 8 9 0
# 10 11 12 0
Useful links
- Learn Python: https://pythonbasics.org
- Download Python: https://python.org