Python Conditionals

Essential Question​

How can a program make decisions about whether or not to run code?

​

​Objective

I can write code that decides whether or not to perform an action

Define: conditional

• Code structure

• Lets us make decisions

• Do a section of code or skip it

• "If yes, then do something"

• Example: "If it is raining, then I'll bring an umbrella."

Define: if-clause/then-block

• if-clause in code is the condition:

• if-clause decides whether or not to proceed with the then-block

• ​

  then-block has at least one line of code

  then-block can either be executed or skipped depending on the if-clause

Structure of a Conditional

• Two parts: if-clause and then-block

• then-block is indented under if-clause

• ​Words go in quote marks, numbers don't

• ​Don't forget the colon!

• Define: comparison operators

• ​Comparison Operators are the symbols that help determine if a conditional is true or false. You might recognize them from your math class - but with a twist!

• ​

  1. < less than

  2. <= less than or equal to

  3. > greater than

  4. >= greater than or equal to

  5. == equal to

  6. != not equal to

What is a valid condition?

• Part of the if-clause

• Asks a yes or no question

• Usually contains an expression (a comparison of value)

• Often uses comparison operators

​