PHP – If Else
<?php
// -----------
// if
// -----------
$t=date("H");
if ($t<"20")
{
echo "Have a good day!";
}
// -----------
// if ... else
// -----------
$t=date("H");
if ($t<"20")
{
echo "Have a good day!";
}
else
{
echo "Have a good night!";
}
// -----------
// if ... elseif ... else
// -----------
$t=date("H");
if ($t<"10")
{
echo "Have a good morning!";
}
elseif ($t<"20")
{
echo "Have a good day!";
}
else
{
echo "Have a good night!";
}
?>
PHP – String Manipulation
The most used functions for String Manipulation:
<?php
// ---------------------------------------------------------------
// String Operators
$a = "Hello";
$b = $a . " world!"; // Concatenation
echo $b; // outputs Hello world!
$x="Hello";
$x .= " world!"; // Concatenation Assignement
echo $x; // outputs Hello world!
// ---------------------------------------------------------------
// strlen - To return the lenght of the string, blank spaces included
echo strlen("Hello world!"); // the result is - 12 -
// ---------------------------------------------------------------
// strpos - To search for a specified character or text within a string.
// If a match is found, it will return the character position of the first match. If no match is found, it will return FALSE.
// The first character position in the string is 0, and not 1.
echo strpos("Hello world!","world"); // the result is 6
// ---------------------------------------------------------------
// trim - Strip (Remove) whitespace (or other characters) from the beginning and end of a string
$text = "Hello World";
echo $text; // Output: Hello World
echo '<br>';
echo trim($text, "Hello"); // Output: World
echo trim($text, "Hd"); // Output: ello Worl
// str_replace - Replace all occurrences of the search string with the replacement string
$phrase = "You should eat fruits, vegetables, and fiber every day.";
$healthy = array("fruits", "vegetables", "fiber");
$yummy = array("pizza", "beer", "ice cream");
echo $newphrase = str_replace($healthy, $yummy, $phrase);
// Output: You should eat pizza, beer, and ice cream every day
// ---------------------------------------------------------------
// substr - Returns the portion of string specified by the start and length parameters.
echo substr("abcdef", -1); // Output: "f"
echo substr("abcdef", -2); // Output: "ef"
echo substr("abcdef", -3, 1); // Output: "d"
// ---------------------------------------------------------------
// stripslashes - Remove backslashes
$str = "Is your name O\'reilly?";
echo stripslashes($str); // Output: Is your name O'reilly?
// ---------------------------------------------------------------
// strip_tags - Remove HTML and PHP tags
$text = '<p>Test paragraph.</p><!-- Comment --> <a href="#fragment">Other text</a>';
echo $text; // Output HTML formatted text
echo strip_tags($text); // Output plain text
// ---------------------------------------------------------------
// strtolower - Make a string lowercase
$str = "Mary Had A Little Lamb and She LOVED It So";
$str = strtolower($str);
echo $str; // Output: mary had a little lamb and she loved it so
// ---------------------------------------------------------------
?>
All string functions at: http://www.php.net/manual/en/ref.strings.php
PHP – Echo – Print
echo -> can output one or more strings, echo does not return any value.
print -> can only output one string, and returns always 1.
<?php
// echo of Strings
// ------------------
echo "<h2>PHP with HTML tags inside</h2>";
echo "This", " string", " was", " made", " with multiple parameters.";
// echo of variables
// ------------------
$txt1="I like PHP";
$txt2="blog.lucedigitale.com";
$cars=array("Volvo","BMW","Toyota");
echo $txt1;
echo "<br>";
echo "Study PHP at $txt2";
echo "My car is a {$cars[0]}";
// print of Strings
// ------------------
print "<h2>PHP is fun!</h2>";
print "Hello world!<br>";
print "I'm about to learn PHP!";
// print of variables
// ------------------
$txt1="I like PHP";
$txt2="blog.lucedigitale.com";
$cars=array("Volvo","BMW","Toyota");
print $txt1;
print "<br>";
print "Study PHP at $txt2";
print "My car is a {$cars[0]}";
?>
PHP – Operators
<?php $x=10; $y=6; echo ($x + $y); // outputs 16 echo ($x - $y); // outputs 4 echo ($x * $y); // outputs 60 echo ($x / $y); // outputs 1.6666666666667 echo ($x % $y); // outputs 4 ?>
<?php $x=10; echo $x; // outputs 10 $y=20; $y += 100; echo $y; // outputs 120 $z=50; $z -= 25; echo $z; // outputs 25 $i=5; $i *= 6; echo $i; // outputs 30 $j=10; $j /= 5; echo $j; // outputs 2 $k=15; $k %= 4; echo $k; // outputs 3 ?>
<?php $a = "Hello"; $b = $a . " world!"; echo $b; // outputs Hello world! $x="Hello"; $x .= " world!"; echo $x; // outputs Hello world! ?>
<?php $x=10; echo ++$x; // outputs 11 first -> the increment starts echo ++$x; // outputs 12 -> the incrementt continues... $y=10; echo $y++; // outputs 10 first -> the value in the same echo $y++; // outputs 11 second -> the increment starts $z=5; echo --$z; // outputs 4 first -> the decrement starts echo --$z; // outputs 3 second -> the decrement continues... $i=5; echo $i--; // outputs 5 first -> the value in the same echo $i--; // outputs 4 second -> the decrement starts ?>
== Equal $x == $y True if $x is equal to $y
=== Identical $x === $y True if $x is equal to $y, and they are of the same type
!= Not equal $x != $y True if $x is not equal to $y
<> Not equal $x <> $y True if $x is not equal to $y
!== Not identical $x !== $y True if $x is not equal to $y, or they are not of the same type
> Greater than $x > $y True if $x is greater than $y
< Less than $x < $y True if $x is less than $y
>= Greater than or equal to $x >= $y True if $x is greater than or equal to $y
<= Less than or equal to $x <= $y True if $x is less than or equal to $y
[php]
<?php
$x=100; // It is an integer number
$y="100"; // It is a string
var_dump($x == $y); // Output: bool(true)
echo "<br>";
var_dump($x === $y); // Output: bool(false)
echo "<br>";
var_dump($x != $y); // Output: bool(false)
echo "<br>";
var_dump($x !== $y); // Output: bool(true)
echo "<br>";
$a=50;
$b=90;
var_dump($a > $b); // Output: bool(false)
echo "<br>";
var_dump($a < $b); // Output: bool(true)
?>
[/php]
and And $x and $y True if both $x and $y are true
or Or $x or $y True if either $x or $y is true
xor Xor $x xor $y True if either $x or $y is true, but not both
&& And $x && $y True if both $x and $y are true
|| Or $x || $y True if either $x or $y is true
! Not !$x True if $x is not true
+ Union $x + $y Union of $x and $y (but duplicate keys are not overwritten)
== Equality $x == $y True if $x and $y have the same key/value pairs
=== Identity $x === $y True if $x and $y have the same key/value pairs in the same order and of the same types
!= Inequality $x != $y True if $x is not equal to $y
<> Inequality $x <> $y True if $x is not equal to $y
!== Non-identity $x !== $y True if $x is not identical to $y
<?php
$x = array("a" => "red", "b" => "green");
$y = array("c" => "blue", "d" => "yellow");
$z = $x + $y;
var_dump($z); // Output: array(4) { ["a"]=> string(3) "red" ["b"]=> string(5) "green" ["c"]=> string(4) "blue" ["d"]=> string(6) "yellow" }
var_dump($x == $y); // Output: bool(false)
var_dump($x === $y); // Output: bool(false)
var_dump($x != $y); // Output: bool(true)
var_dump($x <> $y); // Output: bool(true)
var_dump($x !== $y); // Output: bool(true)
?>
PHP – Constants
A constant is an identifier (name) for a simple value. The value cannot be changed during the script.
A valid constant name starts with a letter or underscore (no $ sign before the constant name).
Unlike variables, constants are automatically global across the entire script.
To set a constant, use the define() function.
Statement:
define(“GREETING”, “Welcome to W3Schools.com!”, true);
define(“constant name”, “constat value”, case-insensitive true/false);
<?php
// define a case-insensitive constant
define("GREETING", "Welcome to W3Schools.com!", true);
echo GREETING;
echo "<br>";
// will also output the value of the constant
echo greeting; // case-insensitive
?>
