PHP - if elseif else statements

by
Jeremy Canfield |
Updated: May 25 2024
| PHP articles
An if elsif statement in PHP has the following structure.
if (comparison) {
--do something--
}
elseif (comparison) {
--do something--
}
else {
--do something
}
For example.
if ($foo == 10) {
echo "foo equals 10.";
}
elseif ($foo == 20) {
echo "foo equals 20.";
}
else {
echo "foo does not equal 10 or 20.";
}
Following are common if statements.
Equals string Equals boolean |
if ($foo == "Hello World") if ($foo == true) |
Does not equal string Does not equal boolean |
if ($foo != "Hello World") if ($foo != true) |
Greater than |
tbd |
Less than |
tbd |
Greater than or equal to |
tbd |
Less than or equal to |
tbd |
If file or directory exists |
if (file_exists('/path/to/foo.txt')) |
If URL exists | see http://www.freekb.net/Article?id=3525 |
If variable is defined | if (isset($foo)) |
If variable is not defined | if (!isset($foo)) |
If variable is empty (null) | if (empty($foo)) |
If variable is not empty (not null) | if (!empty($foo)) |
If array is empty (null) | if (empty($array)) |
If array is not empty (not null) | if (!empty($array)) |
If variable contains |
if (preg_match('/hello|world/i', $foo)) |
If variable does not contain | if (!preg_match('/hello|world/i', $foo)) |
If array contains | if (in_array("bar", $foo )) |
If array does not contain | if (!in_array("bar", $foo )) |
If array contains exact match | tbd |
If array does not contain exact match | tbd |
If hash contains | tbd |
If hash does not contain | tbd |
If file contains / does not contain | tbd |
If string begins with | if (preg_match('/^(hello|world)/i', $foo)) |
If string does not begin with | if (!preg_match('/^(hello|world)/i', $foo)) |
If string ends with | if (preg_match('/(hello|world)$/i', $foo)) |
If string does not end with | if (!preg_match('/(hello|world)$/i', $foo)) |
Multiple conditions
Here is one way to handle multiple conditions.
if (($foo == "Hello") or ($foo == "World")) {
echo "foo equals Hello or World";
}
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