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array_walk(3) [php man page]

ARRAY_WALK(3)								 1							     ARRAY_WALK(3)

array_walk - Apply a user supplied function to every member of an array

bool array_walk NULL (array &$array, callable $callback, [mixed $userdata]) DESCRIPTION
Applies the user-defined $callback function to each element of the $array array. array_walk(3) is not affected by the internal array pointer of $array. array_walk(3) will walk through the entire array regardless of pointer position. PARAMETERS
o $array - The input array. o $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 refer- ence. Then, any changes made to those elements will be made in the original array itself. Note Many internal functions (for example strtolower(3)) will throw a warning if more than the expected number of argument are passed in and are not usable directly as a $callback. Only the values of the $array may potentially be changed; its structure cannot be altered, i.e., the programmer cannot add, unset or reorder elements. If the callback does not respect this requirement, the behavior of this function is undefined, and unpre- dictable. o $userdata - If the optional $userdata parameter is supplied, it will be passed as the third parameter to the $callback. RETURN VALUES
Returns TRUE on success or FALSE on failure. ERRORS
/EXCEPTIONS If function $callback requires more parameters than given to it, an error of level E_WARNING will be generated each time array_walk(3) calls $callback. EXAMPLES
Example #1 array_walk(3) example <?php $fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple"); function test_alter(&$item1, $key, $prefix) { $item1 = "$prefix: $item1"; } function test_print($item2, $key) { echo "$key. $item2<br /> "; } echo "Before ...: "; array_walk($fruits, 'test_print'); array_walk($fruits, 'test_alter', 'fruit'); echo "... and after: "; array_walk($fruits, 'test_print'); ?> The above example will output: Before ...: d. lemon a. orange b. banana c. apple d. fruit: lemon a. fruit: orange b. fruit: banana c. fruit: apple SEE ALSO
array_walk_recursive(3), iterator_apply(3), list(3), each(3), call_user_func_array(3), array_map(3), information about the callback type, foreach. PHP Documentation Group ARRAY_WALK(3)

Check Out this Related Man Page

TRIM(3) 								 1								   TRIM(3)

trim - Strip whitespace (or other characters) from the beginning and end of a string

string trim (string $str, [string $character_mask = " 0r B"]) DESCRIPTION
This function returns a string with whitespace stripped from the beginning and end of $str. Without the second parameter, trim(3) will strip these characters: o " " (ASCII 32 ( 0x20)), an ordinary space. o " " (ASCII 9 ( 0x09)), a tab. o " " (ASCII 10 ( 0x0A)), a new line (line feed). o " " (ASCII 13 ( 0x0D)), a carriage return. o "" (ASCII 0 ( 0x00)), the NUL-byte. o "x0B" (ASCII 11 ( 0x0B)), a vertical tab. PARAMETERS
o $str - The string that will be trimmed. o $character_mask - Optionally, the stripped characters can also be specified using the $character_mask parameter. Simply list all characters that you want to be stripped. With .. you can specify a range of characters. RETURN VALUES
The trimmed string. EXAMPLES
Example #1 Usage example of trim(3) <?php $text = " These are a few words :) ... "; $binary = "x09Example stringx0A"; $hello = "Hello World"; var_dump($text, $binary, $hello); print " "; $trimmed = trim($text); var_dump($trimmed); $trimmed = trim($text, " ."); var_dump($trimmed); $trimmed = trim($hello, "Hdle"); var_dump($trimmed); $trimmed = trim($hello, 'HdWr'); var_dump($trimmed); // trim the ASCII control characters at the beginning and end of $binary // (from 0 to 31 inclusive) $clean = trim($binary, "x00..x1F"); var_dump($clean); ?> The above example will output: string(32) " These are a few words :) ... " string(16) " Example string " string(11) "Hello World" string(28) "These are a few words :) ..." string(24) "These are a few words :)" string(5) "o Wor" string(9) "ello Worl" string(14) "Example string" Example #2 Trimming array values with trim(3) <?php function trim_value(&$value) { $value = trim($value); } $fruit = array('apple','banana ', ' cranberry '); var_dump($fruit); array_walk($fruit, 'trim_value'); var_dump($fruit); ?> The above example will output: array(3) { [0]=> string(5) "apple" [1]=> string(7) "banana " [2]=> string(11) " cranberry " } array(3) { [0]=> string(5) "apple" [1]=> string(6) "banana" [2]=> string(9) "cranberry" } NOTES
Note Possible gotcha: removing middle characters Because trim(3) trims characters from the beginning and end of a string, it may be confusing when characters are (or are not) removed from the middle. trim('abc', 'bad') removes both 'a' and 'b' because it trims 'a' thus moving 'b' to the beginning to also be trimmed. So, this is why it "works" whereas trim('abc', 'b') seemingly does not. SEE ALSO
ltrim(3), rtrim(3), str_replace(3). PHP Documentation Group TRIM(3)

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