A Tour of Decision Making Structures in PHP - Comparison Operators
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The following chart shows some common operators you may use in your programs.
operator comparison
------------------------------------------------
x == y checks if the value of x is equal to
the value of y
x != y checks if the value of x is not
equal to the value of y
x < y checks if the value of x is less
than the value of y
x > y checks if the value of x is greater
than the value of y
x <= y checks if the value of x is less
than or equal to the value of y
x >= y checks if the value of x is greater
than or equal to the value of y
(a) && (b) checks if the value of statement a
and statement b evaluate to "true"
(a) || (b) checks if the value of statement a
or statement b evaluate to "true" |
Let's apply that information to some example comparisons. Assuming $x holds the value 5, $y holds 100 and $z holds 500:
($x == $y) && ($x <= $z)
(5 == 100) && (5 <= 500)
false && true
> false
($x * $y) == $z
(5 * 100) == 500
500 == 500
> true
($x != $y) || ($y == $z)
(5 != 100) || (100 == 500)
true || false
> true |
Be sure that you don't confuse = with ==. = assigns a value to a variable while == compares for equality. This can be a source of great frustration for many new programmers until they become more accustomed to working with them.
Next: IF Statements >>
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