Programming PHP

Table 2-7. Type of comparision performed by the comparision operators
First operand Second operand Comparison
Number Number Numeric
String that is entirely numeric String that is entirely numeric Numeric
String that is entirely numeric Number Numeric
String that is not entirely numeric Number Lexicographic
String that is entirely numeric String that is not entirely numeric Lexicographic
String that is not entirely numeric String that is not entirely numeric Lexicographic
One important thing to note is that two numeric strings are compared as if they were
numbers. If you have two strings that consist entirely of numeric characters and you
need to compare them lexicographically, use the strcmp( ) function.
The comparison operators are:
Equality (==)
If both operands are equal, this operator returns true; otherwise, it returns false.
Identical (===)
If both operands are equal and are of the same type, this operator returns true;
otherwise, it returns false. Note that this operator does not do implicit type
casting. This operator is useful when you don’t know if the values you’re comparing
are of the same type. Simple comparison may involve value conversion.
For instance, the strings "0.0" and "0" are not equal. The == operator says they
are, but === says they are not.
Inequality (!= or )
If both operands are not equal, this operator returns true; otherwise, it returns
false.
Not identical (!==)
If both operands are not equal, or they are not of the same type, this operator
returns true; otherwise, it returns false.
Greater than (>)
If the lefthand operator is greater than the righthand operator, this operator
returns true; otherwise, it returns false.
Greater than or equal to (>=)
If the lefthand operator is greater than or equal to the righthand operator, this
operator returns true; otherwise, it returns false.
Less than (