If...
The first type of condition we will look at is documentationif, which has the following syntax:
if (condition) {
statement
}
Again, the syntax is very close to ordinary English: If a condition is met, then execute something. Let's look at a simple example:
<html>
<head>
<title>Loops </title>
</head>
<body>
<?php
$x = 2;
if ($x > 1) {
echo "<p>variable $x is greater than 1 </p>";
}
?>
</body>
</html>
if ... else ...
The next type of condition will want to look at is documentationelse , which may be presented in the following form:
if (condition) {
statement
}
else {
statement
}
Again, the syntax is very close to ordinary English: if a condition is met execute something or else execute something else.
Example:
we will use the month number in an documentationif documentationelse condition to find out what season it is:
<html>
<head>
<title>Conditions</title>
</head>
<body>
<?php
if (date ("m") == 3) {
echo "<p>Now it's spring!</p> ";
}
else {
echo "<p>I do not know what season it is!</p> ";
}
?>
</body>
</html>
However, there are plenty of ways to improve the condition and make it more precise. Below are listed comparison operators that can be used in the condition:
== Equals
< Less than
> Greater than
<= Less than or equal to
>= Greater than or equal to
!= Not equal to
In addition, there are some logical operators:
&& And
|| Or
! Not
The operators can be used to develop more precise conditions, so now we can expand the above example to include all the spring months:
<html>
<head>
<title>Conditions</title>
</head>
<body>
<?php
if (date("m") >= 3 && date("m") <= 5) {
echo "<p> Now it's spring!</p> ";
}
else {
echo "<p> Now it's either winter, summer or autumn!</p> ";
}
?>
</body>
</html>
Let's take a closer look at the extended condition:
date("m") >= 3 && date("m") <= 5
The condition can be translated into:
If the month is greater than or equal to 3,
and the month is less than or equal to 5
if ... elseif ... else...
Using documentationelseif, we can expand the condition and make it work for all months:
<html>
<head>
<title>Conditions</title>
</head>
<body>
<?php
if (date("m") >= 3 && date("m") <= 5) {
echo "<p>Now it's spring!</p>";
}
elseif (date("m") >= 6 && date("m") <= 8) {
echo "<p>Now it's summer!</p>";
}
elseif (date("m") >= 9 && date("m") <= 11) {
echo "<p>Now it's autumn!</p>";
}
else {
echo "<p>Now is winter!</p>";
}
?>
</body>
</html>
switch ... case
Another way of writing conditions is to use the documentationswitch method:switch (expression) {
case 1:
statement
break;
case 2:
statement
break;
default:
statement
break;
}
Example:
<html>
<head>
<title>Conditions</title>
</head>
<body>
<?php
switch(date("w")) {
case 1:
echo "Now it's Monday";
break;
case 2:
echo "Now it's Tuesday";
break;
case 3:
echo "Now it's Wednesday";
break;
case 4:
echo "Now it's Thursday";
break;
case 5:
echo "Now it's Friday";
break;
case 6:
echo "Now it's Saturday";
break;
default:
echo "Now it's Sunday";
break;
}
?>
</body>
</html>
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