Job Ready Python

Lesson 5Using Python Control Statements

Python supports a variety of control structures that determine how content in a program will work and interact. This module explores those control structures that make creating algorithms possible.

LEARNING OBJECTIVES

By the end of this lesson, you will be able to:

• Use an if statement to determine the outcome of a program.
• Use an if-else statement to define two potential outcomes.
• Use nested if statements to define more than two potential outcomes.

CONTROL STRUCTURES REVIEW

Computers understand only machine language, which uses only binary code (represented as 0s and 1s for humans), but it is hard for humans to write code in binary. As a result, programmers create algorithms within a specified programming language (such as Python) that instruct the computer on the specific actions to take to reach the desired outcome. As programmers code and subsequently compile the code, the compiled code translates from the high-level language (in this case, Python) to the machine-level language that can be understood by the computer. This translation from high-level to low-level language allows the computer to execute the directions given.

In order for a problem to be “computable,” an algorithm must be constructed. If programmers are unable to build an algorithm, we say that the problem cannot be computed. However, if the problem is solvable, the instructions can be presented using three important control structures:

• Sequence
• Selection