PHP: implode() function
Description
The implode() function is used to join array elements with a string.
Version:
(PHP 4 and above)
Syntax:
implode (string_join, array_name)
Parameters:
Name | Description | Required / Optional |
Type |
---|---|---|---|
string_join | String-join works as a connector between the array elements. The default value is a empty string (" "). | Optional | String |
array_name | The array who's elements will be joined. | Required | Array |
Return values:
A string representation of all the array elements in the same order, with the string_join string between each array element.
Value Type: String.
Pictorial Presentation
Example:
<?php
$array_name=array('First Name', 'Middle Name', 'Last Name');
$join_string=implode("-", $array_name);
echo $join_string;
echo '<br>';
$join_string=implode(" ", $array_name);
echo $join_string;
?>
Output:
First Name-Middle Name-Last Name First Name Middle Name Last Name
View the example in the browser
See also
Previous: htmlspecialchars
Next: join
PHP: Tips of the Day
PHP - How do I implement a callback in PHP?
The manual uses the terms "callback" and "callable" interchangeably, however, "callback" traditionally refers to a string or array value that acts like a function pointer, referencing a function or class method for future invocation. This has allowed some elements of functional programming since PHP 4. The flavors are:
$cb1 = 'someGlobalFunction'; $cb2 = ['ClassName', 'someStaticMethod']; $cb3 = [$object, 'somePublicMethod']; // this syntax is callable since PHP 5.2.3 but a string containing it // cannot be called directly $cb2 = 'ClassName::someStaticMethod'; $cb2(); // fatal error // legacy syntax for PHP 4 $cb3 = array(&$object, 'somePublicMethod');
This is a safe way to use callable values in general:
if (is_callable($cb2)) { // Autoloading will be invoked to load the class "ClassName" if it's not // yet defined, and PHP will check that the class has a method // "someStaticMethod". Note that is_callable() will NOT verify that the // method can safely be executed in static context. $returnValue = call_user_func($cb2, $arg1, $arg2); }
Modern PHP versions allow the first three formats above to be invoked directly as $cb(). call_user_func and call_user_func_array support all the above.
Notes/Caveats:
- If the function/class is namespaced, the string must contain the fully-qualified name. E.g. ['Vendor\Package\Foo', 'method']
- call_user_func does not support passing non-objects by reference, so you can either use call_user_func_array or, in later PHP versions, save the callback to a var and use the direct syntax: $cb();
- Objects with an __invoke() method (including anonymous functions) fall under the category "callable" and can be used the same way, but I personally don't associate these with the legacy "callback" term.
- The legacy create_function() creates a global function and returns its name. It's a wrapper for eval() and anonymous functions should be used instead.
Ref : https://bit.ly/2Zmqil0
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