1. Decisions In today’s lesson we will look at:
what we mean by a decision
the sorts of decisions a program might need to take
programming a decision in Python

2. Decisions
We need to make decisions all the time – what time to get up, what to eat, how to start your essay, etc.
In programming, the word decision has the same sort of meaning.
Can you think of a program that does exactly the same thing every time?
Most programs make some sort of decision

3. Decisions
What sort of things will your program make decisions based on?
Your program might need to react to:
what the user does
what happens in the program
the values of particular variables
an external factor, such as date or time

4. Programming Decisions
Most programming languages – and even spreadsheets – use an if command to make a decision
In Python, the format is:
if [test condition]:
[command]
For example...
if x > 10: print(“X is bigger than 10”)

5. Multiple Commands
There is an expanded form of IF that allows you to do more than one thing:
if a > b:
a = a + b
b = a – b
a = a – b
print(“Always done”)

6. Alternatives You can also use the ELSE command to give an alternative:
if a > 10:
print(“a is bigger than 10”)
else:
print(“a isn’t bigger than 10”)
print(“Always done”)