Python runs one statement after another. print writes to the cell output. A # starts a comment.

Goal

Run print, a comment, and see the difference between print(x) and a bare x.

First cell

print("Hello, Python")
print("Swiftener notebook")

Comments and multiple prints

# This line is ignored.
print("Ada")
print("Alan")
print("Grace")

"Nairobi"

The notebook shows 'Nairobi' because it is the last expression. Compare:

city = "Nairobi"
print("printed:", city)
city

print("about to fail")
print(unknown_name)

You should see a NameError and a traceback. The next chapter puts names on the left of =.

Tip

If nothing appears, the cell is empty, still loading Python, or you ran a markdown cell. Check the status line, then Shift+Enter on a code cell.