PHP Array extract() Function
What is extract() Function?
Explanation
The "extract()" function import variables into the current symbol table from an array. This function uses array keys as variable names, values as variable values. For each element it will create a variable in the current symbol table
extract(array,extract_rules,prefix)
In the above syntax "array" is the array from which the variables are imported to the current symbol table.
The following is the description of the Extract_rules parameters.
The "prefix" parameter is seperated by an underscore, both "extract rules", "prefix" are optional parameters.
<?php
$size = "large";
$var_array = array("color" => "blue",
"size" => "medium",
"shape" => "sphere");
extract($var_array, EXTR_PREFIX_SAME, "dup");
echo "$color, $size, $shape, $dup_sizen";
?> Result :
blue, large, sphere, medium
In the above example there is a collision for the variable "$size" so using the extracting rule "EXTR_PREFIX_SAME", the variable $size value that is "large" is added for size and using the prefix "dup" with size, the value "medium" is displayed.
Syntax:
extract(array,extract_rules,prefix)
In the above syntax "array" is the array from which the variables are imported to the current symbol table.
The following is the description of the Extract_rules parameters.
| Parameter | Description |
| EXTR_OVERWRITE | If there is a collision, overwrite the existing variable. |
| EXTR_SKIP | If there is a collision, don't overwrite the existing variable. |
| EXTR_PREFIX_SAME | If there is a collision, prefix the variable name with prefix. |
| EXTR_PREFIX_ALL | Prefix all variable names with prefix. |
| EXTR_PREFIX_INVALID | Only invalid or numeric variable names will be given a prefix./td> |
| EXTR_IF_EXISTS | Only overwrite existing variables in the current symbol table, otherwise do nothing |
| EXTR_PREFIX_IF_EXISTS | Only add prefix to variables if the same variable exists in the current symbol table. |
| EXTR_REFS | Extracts variables as references. The imported variables are still referencing the values of the array parameter. |
The "prefix" parameter is seperated by an underscore, both "extract rules", "prefix" are optional parameters.
Example :
<?php
$size = "large";
$var_array = array("color" => "blue",
"size" => "medium",
"shape" => "sphere");
extract($var_array, EXTR_PREFIX_SAME, "dup");
echo "$color, $size, $shape, $dup_sizen";
?>
blue, large, sphere, medium
In the above example there is a collision for the variable "$size" so using the extracting rule "EXTR_PREFIX_SAME", the variable $size value that is "large" is added for size and using the prefix "dup" with size, the value "medium" is displayed.
