Variables and Expressions

Question 1

what are variables?

Answer 1

variables are a way of giving names to data so that the computer can remember the data

Question 2

what constraints must variable names follow in Python?

Answer 2

• may contain letters of digits, but cannot start with a digit
• may contain underscore characters and may start with an underscore
• may not contain spaces or other special characters

Question 3

what is variable assignment?

Answer 3

the process of giving a valid name to a piece of data

Question 4

what are expressions?

Answer 4

combinations of data and operators

Question 5

what are operators?

Answer 5

special symbols which have specific meaning in the programming language. they perform computations on one or more pieces of data to produce a new piece of data

Question 6

what three distinct components of a computer program does the Model-View-Controller pattern emphasize?

Answer 6

• the model is the computer’s internal representation of a problem or environment
• a view is a method of displaying the program’s model to a human user
• a controller is a method for a human user to modify the model

Question 7

what are local variables used for?

Answer 7

to store intermediate values

Question 8

what are global values used for?

Answer 8

to store persistent values (values that are relevant to multiple parts of our program)