Programming PHP

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Because if is a statement, you can chain them:
if ($good)
print('Dandy!');
else
if ($error)
print('Oh, no!');
else
print("I'm ambivalent...");
Such chains of if statements are common enough that PHP provides an easier syntax:
the elseif statement. For example, the previous code can be rewritten as:
if ($good)
print('Dandy!');
elseif ($error)
print('Oh, no!');
else
print("I'm ambivalent...");
The ternary conditional operator (?:) can be used to shorten simple true/false tests.
Take a common situation such as checking to see if a given variable is true and printing
something if it is. With a normal if/else statement, it looks like this:
With the ternary conditional operator, it looks like this:
Compare the syntax of the two:
if (expression) true_statement else false_statement
(expression) ? true_expression : false_expression
The main difference here is that the conditional operator is not a statement at all.
This means that it is used on expressions, and the result of a complete ternary
expression is itself an expression. In the previous example, the echo statement is
inside the if condition, while when used with the ternary operator, it precedes the
expression.
switch
It often is the case that the value of a single variable may determine one of a number
of different choices (e.g., the variable holds the username and you want to do
something different for each user). The switch statement is designed for just this
situation.
48 | Chapter 2: Language Basics
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