Applies the user-defined
callback
function to each element of the
array
. This function will recurse into deeper arrays.
Parameters
array
The input array.
callback
Typically,
callback
takes on two parameters. The
array
parameter's value being the first, and the key/index second.
Note
:
If
callback
needs to be working with the actual values of the array, specify the first parameter of
callback
as a reference. Then, any changes made to those elements will be made in the original array itself.
arg
If the optional
arg
parameter is supplied, it will be passed as the third parameter to the
callback
.
You may notice that the key '
sweet
' is never displayed. Any key that holds an
array
will not be passed to the function.
See Also
array_walk() - Apply a user supplied function to every member of an array
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Creates an array containing variables and their values.
For each of these,
compact()
looks for a variable with that name in the current symbol table and adds it to the output array such that the variable name becomes the key and the contents of the variable become the value for that key. In short, it does the opposite of
extract()
.
Note
:
Before PHP 7.3, any strings that are not set will silently be skipped.
Parameters
var_name
var_names
compact()
takes a variable number of parameters. Each parameter can be either a string containing the name of the variable, or an array of variable names. The array can contain other arrays of variable names inside it;
compact()
handles it recursively.
Return Values
Returns the output array with all the variables added to it.
Errors/Exceptions
compact()
issues an E_NOTICE level error if a given string refers to an unset variable.
Changelog
Version
Description
7.3.0
compact()
now issues an E_NOTICE level error if a given string refers to an unset variable. Formerly, such strings have been silently skipped.
Counts all elements in an array when used with an array. When used with an object that implements the
Countable
interface, it returns the return value of the method
Countable::count()
.
Parameters
value
An array or
Countable
object.
mode
If the optional
mode
parameter is set to
COUNT_RECURSIVE
(or 1),
count()
will recursively count the array. This is particularly useful for counting all the elements of a multidimensional array.
Caution
count()
can detect recursion to avoid an infinite loop, but will emit an
E_WARNING
every time it does (in case the array contains itself more than once) and return a count higher than may be expected.
Return Values
Returns the number of elements in
value
. Prior to PHP 8.0.0, if the parameter was neither an
array
nor an
object
that implements the
Countable
interface,
1
would be returned, unless
value
was
null
, in which case
0
would be returned.
Changelog
Version
Description
8.0.0
count()
will now throw
TypeError
on invalid countable types passed to the
value
parameter.
7.2.0
count()
will now yield a warning on invalid countable types passed to the
value
parameter.
int(3)
Warning: count(): Parameter must be an array or an object that implements Countable in … on line 12
int(0)
Warning: count(): Parameter must be an array or an object that implements Countable in … on line 14
int(1)
Output of the above example in PHP 8:
int(3)
Fatal error: Uncaught TypeError: count(): Argument #1 ($var) must be of type Countable .. on line 12
Example #3 Recursive
count()
example
<?php$food=array('fruits'=>array('orange','banana','apple'),'veggie'=>array('carrot','collard','pea'));// recursive countvar_dump(count($food,COUNT_RECURSIVE));// normal countvar_dump(count($food));?>
Every array has an internal pointer to its "current" element, which is initialized to the first element inserted into the array.
Parameters
array
The array.
Return Values
The
current()
function simply returns the value of the array element that's currently being pointed to by the internal pointer. It does not move the pointer in any way. If the internal pointer points beyond the end of the elements list or the array is empty,
current()
returns
false
.
Warning
This function may return Boolean
false
, but may also return a non-Boolean value which evaluates to
false
. Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.
Changelog
Version
Description
8.1.0
Calling this function on
object
s is deprecated. Either use
get_mangled_object_vars()
on the
object
first, or use
ArrayIterator
.
Note
:
The results of calling
current()
on an empty array and on an array, whose internal pointer points beyond the end of the elements, are indistinguishable from a
bool
false
element. To properly traverse an array which may contain
false
elements, see the foreach control structure.
To still use
current()
and properly check if the value is really an element of the array, the
key()
of the
current()
element should be checked to be strictly different from
null
.
See Also
end() - Set the internal pointer of an array to its last element
key() - Fetch a key from an array
each() - Return the current key and value pair from an array and advance the array cursor
prev() - Rewind the internal array pointer
reset() - Set the internal pointer of an array to its first element