Expressions
Expressions in PHP are formulated in much the same way as other languages. An expression is formed from literal values (integers, strings, floats, Booleans, arrays, and objects), operators, and function calls that return values. An expression has a value and a type; for example, the expression 4 + 7 has the value 11 and the type integer, and the expression "Kelpie" has the value Kelpie and the type string. PHP automatically converts types when combining values in an expression. For example, the expression 4 + 7.0 contains an integer and a float; in this case, PHP considers the integer as a floating-point number, and the result is a float. The type conversions are largely straightforward; however, there are some traps, which are discussed later in this section.