M&C8: Incorrect use of strings, integers, and variable names

Consider the statements below

John = 5
friend_name = John
print friend_name
print type(friend_name)

What is printed?


Variable friend_name gets the value of integer 5.  If we wanted friend_name to contain the string “John”, we would have to write friend_name = “John”. Make sure students understand the type of each variable in situations when multiple types are being used.

A common mistake when using a string and an integer:

my_number = '5' 	# a string '5'

count = 5 			# an integer 5

What is the value of the expression (my_number == count)? We are comparing a string containing ‘5’ with an integer having value 5. The result will be False.

We can add integers and the + operator also exists for strings (it concatenates two strings).

What does count + my_number produce? 10 or 55?  It produces a TypeError as shown below.