Comment code with this type of comment as follows:

>>> # Comment from hash to end of line

However, if the hash sign is between single or double quotes, then we have a string, which is an ordered sequence of characters:

>>> astring = '# This is not a comment'
>>> astring
'# This is not a comment'

We can also comment multiple lines as a block. This is useful if you want to write a more detailed description of the code. Comment multiple lines as follows:

"""
 Chapter 1 of NumPy Beginners Guide.
 Another line of comment.
"""

We refer to this type of comment as triple-quoted for obvious reasons. It also is used to test code. You can read about testing in Chapter 8, Assuring Quality with Testing.