Detailed explanation and example code of php array processing function extract_php example

php array processing function extract

The extract function is used to import variables from an array into the current symbol table

Basic Grammar

int extract ( array &$var_array [, int $extract_type = EXTR_OVERWRITE [, string $prefix = NULL ]] )

This function is used to import variables from the array into the current symbol table. Each key name is checked to see if it can be used as a legal variable name, and is also checked for conflicts with existing variable names in the symbol table.

Parameter introduction:

Parameters	Description
var_array	Required. Specifies the array to use. An associative array. This function treats the key name as the variable name and the value as the variable's value. For each key/value pair a variable is created in the current symbol table, affected by the extract_type and prefix parameters. Associative arrays must be used, numerically indexed arrays will not produce results unless EXTR_PREFIX_ALL or EXTR_PREFIX_INVALID is used.
extract_type	Optional. The extract() function will check whether each key name is a legal variable name, and also checks whether it conflicts with an existing variable name in the symbol table. The handling of illegal and conflicting key names will be determined based on this parameter. Possible values: EXTR_OVERWRITE - Default. If there is a conflict, existing variables are overwritten. EXTR_SKIP - Do not overwrite existing variables if there is a conflict. EXTR_PREFIX_SAME - If there is a conflict, prefix the variable name with prefix. EXTR_PREFIX_ALL - Prefix all variable names with prefix. EXTR_PREFIX_INVALID - Only prefix illegal or numeric variable names. EXTR_IF_EXISTS - Only overwrite the values ​​of variables with the same name if they already exist in the current symbol table. Others are not processed. EXTR_PREFIX_IF_EXISTS - Only when there is a variable with the same name in the current symbol table, the variable name with the prefix is ​​created, and the others are not processed. EXTR_REFS - Extract variables as references. The imported variable still references the value of the array parameter.
prefix	Optional. Note that prefix is ​​only required if the value of extract_type is EXTR_PREFIX_SAME, EXTR_PREFIX_ALL, EXTR_PREFIX_INVALID or EXTR_PREFIX_IF_EXISTS. If the result after appending the prefix is ​​not a legal variable name, it will not be imported into the symbol table. An underscore is automatically added between the prefix and the array key name.

Return value

Returns the number of variables successfully imported into the symbol table.

Example:

<&#63;php
$size = "large";
$var_array = array(
  "color" => "blue",
  "size" => "medium",
  "shape" => "sphere"
);
extract($var_array, EXTR_PREFIX_SAME, "wddx");
echo " $color , $size , $shape , $wddx_size <br/>";
&#63;>  

Run result:

blue, large, sphere, medium

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