In life, we all have to make decisions. To say yes or to say no, to buy or not to buy, to shake or to stir, to... you get the point. Our apps also have to make decisions based on conditions, and Lua has provided you with a way to do so.
Our first decision statement is the if-then statement. The if-then statement will perform an action based on the result of a condition. Every if-then statement follows a standard layout: test a condition, and if true, perform an action. Here's an example:
if(age < 29) then
print('You are not quite 30!'),
endTip
Downloading the example code
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Let's break down our if-then statement so we understand what's happening:
- We let our app know we are starting a decision process with the keyword
if. - Next, we enclose a conditional statement with a pair of parentheses. Inside the parentheses, we are comparing two values to each other using the less than operator. When comparing a text value, we need to wrap the value with quotes; otherwise, don't use any quotes.
- After the conditional, we use the keyword
thento state that the action is to be performed only if the condition is true. - Finally, we wrap up the decision process with the keyword
end.
In our sample if-then statement, we are printing the string You are not quite 30! to our Corona Terminal. If our variable age was 29 or higher, nothing would be printed to the terminal.
What should you do when you have to make more than one decision? There's a decision statement for that too—the if-then-else statement.
Every if-then-else statement has a standard layout: test a condition, and if true, perform action 1; otherwise, perform action 2. Let's take a look at an example of an if-then-else statement:
if(player == "James Bond") then
print('Drink Shaken'),
else
print('Drink Stirred'),
endAnd now let's look at a breakdown of the if-then-else statement so we can understand what's happening:
- We start the decision process by using the
ifkeyword. - Next, we enter a conditional statement. In our sample, we are asking our app to test the variable player to the string
James Bond. - If the conditional statement is true, then the decision will perform the first action, which is to print
Drink Shakento our terminal. Otherwise, the decision will perform the second action (else), which says to printDrink Stirredto our terminal.
Both if-then and if-then-else statements are great for pieces of code that need to run conditionally.