PHP
PHP (PHP: Hypertext Preprocessor) is an open-source, reflective programming language. Originally designed as a high level scripting language for producing dynamic Web pages, PHP is used mainly in server-side application software.
Contents
Ternary Operator
Note: See Comparison Operators for details. Another conditional operator is the "?:" (or ternary) operator.
- Assigning a default value:
<?php
// Example usage for: Ternary Operator
$action = (empty($_POST['action'])) ? 'default' : $_POST['action'];
// The above is identical to this if/else statement
if (empty($_POST['action'])) {
$action = 'default';
} else {
$action = $_POST['action'];
}
?>
The expression (expr1) ? (expr2) : (expr3) evaluates to expr2 if expr1 evaluates to TRUE, and expr3 if expr1 evaluates to FALSE.
Note: The ternary operator is a statement, and that it doesn't evaluate to a variable, but to the result of a statement. This is important to know if you want to return a variable by reference. The statement return $var == 42 ? $a : $b; in a return-by-reference function will therefore not work and a warning is issued in later PHP versions.
Sandbox
Inconsistent arguments and return values
To illustrate this problem, below is a table of the functions that match a user defined thing:
replaces case gives s/m/x offset
matches with insens number arrays matches flags (-1=end)
ereg ereg no all no array no 0
ereg_replace ereg str no all no no no 0
eregi ereg yes all no array no 0
eregi_replace ereg str yes all no no no 0
mb_ereg ereg[1] no all no array no 0
mb_ereg_replace ereg[1] str/expr no all no no yes 0
mb_eregi ereg[1] yes all no array no 0
mb_eregi_replace ereg[1] str yes all no no no 0
preg_match preg[2] yes/no one no array yes 0
preg_match_all preg yes/no all no array yes 0
preg_replace preg str/expr yes/no n/all yes no yes 0
str_replace str str no all yes number no 0
str_ireplace str str yes all yes number no 0
strstr, strchr str/char no one no substr no 0
stristr str/char yes one no substr no 0
strrchr char no one no substr no -1
strpos str/char no one no index no n
stripos str/char yes one no index no n
strrpos char[3] no one no index no n
strripos str yes one no index no -1
mb_strpos str[1] no one no index no n
mb_strrpos str[1] yes one no index no -1
[1] Handles multi-byte characters; [2] PCRE regex: so-called "Perl compatible" regular expressions; [3] Also does strings in PHP 5
Note: The same problem exists for other function groups, not just for matching. Also note: In Perl, all the functionality provided by the functions in this table is available through a simple set of 4 operators.
External links
- phpDocumentor
- LibMail — a PHP Mail Class
- Database Simplicity with Class
- Phing
