Exercise 08 - Conditionals

Working with If statements

The false? is asking if the expression that follows is a false statement. If the expression is false, then it satisfies the false? test and returns a true. Being as the statement is true, the first value is returned which is :a. Otherwise the 2nd value is returned.

(if (false? (= 4 5))
  :a
  :b)

;;=> :a

What if there were no second value? If the condition were false and there is no 2nd value, then a nil is returned.

(if (> 4 3)
	:a)

;;=> :a 

(if (> 3 4)
	:a)

;;=> nil

Working with Multiple Paths (cond)

In this example, we can see that there are multiple paths to test against.

    (let [x 5]
    (= :your-road (cond (= x 3) :road-not-taken
                        (= x 4) :another-road-not-taken
                        :else :your-road)))

Testing if a condition isn't true (if-not)

• zero? 1
  • Is this number equal to zero?
    • False
• if-not (false)
  • If the expression is not true, this satisfies the if-not condition meaning its true and the first value will be evaluated.

(if-not (zero? 1)
	:doom
	:gloom)

;;=> :doom