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2010-05-26T07:06:45Z

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==Comparing numbers and strings==



<source lang="html4strict">

<?
// These values are compared using dictionary order
if ("x54321" > "x5678") {
print "The string "x54321" is greater than the string "x5678".";
} else {
print "The string "x54321" is not greater than the string "x5678".";
}

</source>

==Comparison Operators==



<source lang="html4strict">

example name result
$a == $b Equal True if $a is equal to $b.
$a === $b Identical True if $a is equal to $b, and they are of the same type. (PHP4 only)
$a != $b Not equal True if $a is not equal to $b.
$a < $b Less than True if $a is strictly less than $b.
$a > $b Greater than True if $a is strictly greater than $b.
$a <= $b Less than or equal to True if $a is less than or equal to $b.
$a >= $b Greater than or equal to True if $a is greater than or equal to $b.

<?php
$a = ("PHP"=="PHP")? "true":"false";
$b = ("PHP"=="PERL")?"true":"false";
$c = (1.785==1.785)? "true":"false";
$d = (5 != 5)?"true":"false";
$e = (true == true)?"true":"false";
$f = (false != false)?"true":"false";
$g = (100<200)?"true":"false";
$h = (100<100)?"true":"false";
$i = (100<=100)?"true":"false";
$j = ( -1 > 1 )?"true":"false";

$result = "TEST STRINGS \$a:$a \$b:$b ";
$result .= "TEST NUMBERS \$c:$c \$d:$d ";
$result .= "TEST BOOLEANS \$e:$e \$f:$f ";
$result .= "TEST LESS THAN \$g:$g \$h:$h ";
$result .= "TEST LESS THAN OR EQUAL \$i:$i ";
$result .= "TEST GREATER THAN \$j:$j";
?>
<html>
<head>
<title>Comparison Operators</title>
</head>
<body>
<?php echo( $result ); ?>
</body>
</html>

</source>

==Equality Operators in action==



<source lang="html4strict">

<html>
<head>
<title>Equality</title>
</head>
<body>
<?php
$a = 1;
$b = "1";

print("(\$a == \$b)" . (($a == $b) ? "True" : "False") . " ");
print("(\$a != \$b)" . (($a != $b) ? "True" : "False") . " ");
print("(\$a === \$b)" . (($a === $b) ? "True" : "False") . " ");
print("(\$a !== \$b)" . (($a !== $b) ? "True" : "False") . " ");
?>
</body>
</html>

</source>

==Equality Operators summary table==



<source lang="html4strict">



</source>

==Loose Comparison Operators==



<source lang="html4strict">

Example Name Description
$a == $b Equal to True if $ais equal to $b
$a != $b Not equal to True if $ais not equal to $b
$a < $b Less than True if $ais less than $b
$a > $b Greater than True if $ais greater than $b
$a <= $b Less than or equal to True if $ais less than or equal to $b
$a >= $b Greater than or equal to True if $a is greater than or equal to $b
$a === $b Equal to True if $ais equal to $b and they are of the same type
$a !== $b Not equal to True if $ais not equal to $bor they are not of the same type

</source>

==The equality operator==



<source lang="html4strict">

<?
$new_messages = 10
if ($new_messages == 10) {
print "You have ten new messages.";
}
if ($new_messages == $max_messages) {
print "You have the maximum number of messages.";
}

if ($dinner == "B") {
print "B.";
}
?>

</source>

==These values are compared using dictionary order==



<source lang="html4strict">

if ("6 p" < "55 c") {
print ""6 p" is less than than the string "55 c".";
} else {
print ""6 p" is not less than the string "55 c".";
}

</source>

==These values are compared using numeric order==



<source lang="html4strict">

if ("6 p" < 55) {
print ""6 p" is less than the number 55.";
} else {
print ""6 p" is not less than the number 55.";
}
?>

</source>

==The Ternary Operator==



<source lang="html4strict">

<?
$age = 18;
$agestr = ($age < 16) ? "child" : "adult";
?>

</source>

==Using Comparison Operators in if Statements==



<source lang="html4strict">

<?php
$p = 14;
if ($p < 15) {
echo "Sorry! ";
} else {
echo "Congratulations";
}
?>

</source>

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в 10:37, 26 мая 2010

Admin: 1 версия