The if statement is used to conditionally execute code.

Each expression is evaluated in order until one evaluates as true. Then the statements belonging to that expression are executed. If no expressions evaluate to true and the else portion is present then its statements are executed. Only one set of statements is ever executed and without an else it is possible that no statements are ever executed.

# Example 1
if name
    print 'Hello, [name].'

# Example 2
if name
    print 'Hello, [name].'
else
    print "I don't know your name."

# Example 3
if x < y
    print 'x is smaller'
else if x > y
    print 'x is larger'
else
    print 'x and y are the same'