extract Import variables into the current symbol table from an array &reftitle.description; intextract arrayvar_array intextract_typeEXTR_OVERWRITE stringprefix Import variables from an array into the current symbol table. Checks each key to see whether it has a valid variable name. It also checks for collisions with existing variables in the symbol table. &reftitle.parameters; var_array An associative array. This function treats keys as variable names and values as variable values. For each key/value pair it will create a variable in the current symbol table, subject to extract_type and prefix parameters. You must use an associative array; a numerically indexed array will not produce results unless you use EXTR_PREFIX_ALL or EXTR_PREFIX_INVALID. extract_type The way invalid/numeric keys and collisions are treated is determined by the extract_type. It can be one of the following values: 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 prefix invalid/numeric variable names with prefix. EXTR_IF_EXISTS Only overwrite the variable if it already exists in the current symbol table, otherwise do nothing. This is useful for defining a list of valid variables and then extracting only those variables you have defined out of $_REQUEST, for example. EXTR_PREFIX_IF_EXISTS Only create prefixed variable names if the non-prefixed version of the same variable exists in the current symbol table. EXTR_REFS Extracts variables as references. This effectively means that the values of the imported variables are still referencing the values of the var_array parameter. You can use this flag on its own or combine it with any other flag by OR'ing the extract_type. If extract_type is not specified, it is assumed to be EXTR_OVERWRITE. prefix Note that prefix is only required if extract_type is EXTR_PREFIX_SAME, EXTR_PREFIX_ALL, EXTR_PREFIX_INVALID or EXTR_PREFIX_IF_EXISTS. If the prefixed result is not a valid variable name, it is not imported into the symbol table. Prefixes are automatically separated from the array key by an underscore character. &reftitle.returnvalues; Returns the number of variables successfully imported into the symbol table. &reftitle.changelog; &Version; &Description; 4.3.0 EXTR_REFS was added. 4.2.0 EXTR_IF_EXISTS and EXTR_PREFIX_IF_EXISTS were added. 4.0.5 This function now returns the number of variables extracted. EXTR_PREFIX_INVALID was added. EXTR_PREFIX_ALL includes numeric variables as well. &reftitle.examples; A possible use for extract is to import into the symbol table variables contained in an associative array returned by wddx_deserialize. "blue", "size" => "medium", "shape" => "sphere"); extract($var_array, EXTR_PREFIX_SAME, "wddx"); echo "$color, $size, $shape, $wddx_size\n"; ?> ]]> &example.outputs; The $size wasn't overwritten because we specified EXTR_PREFIX_SAME, which resulted in $wddx_size being created. If EXTR_SKIP was specified, then $wddx_size wouldn't even have been created. EXTR_OVERWRITE would have caused $size to have value "medium", and EXTR_PREFIX_ALL would result in new variables being named $wddx_color, $wddx_size, and $wddx_shape. &reftitle.notes; Do not use extract on untrusted data, like user input (i.e. $_GET, $_FILES, etc.). If you do, for example if you want to run old code that relies on register_globals temporarily, make sure you use one of the non-overwriting extract_type values such as EXTR_SKIP and be aware that you should extract in the same order that's defined in variables_order within the &php.ini;. If you have register_globals turned on and you use extract on $_FILES and specify EXTR_SKIP, you may be surprised at the results. This is not recommended practice and is only documented here for completeness. The use of register_globals is deprecated and calling extract on untrusted data such as $_FILES is, as noted above, a potential security risk. If you encounter this issue, it means that you are using at least two poor coding practices. ]]> You might expect to see something like the following: string(10) "somefile.txt" ["type"]=> string(24) "application/octet-stream" ["tmp_name"]=> string(14) "/tmp/phpgCCPX8" ["error"]=> int(0) ["size"]=> int(4208) } string(14) "/tmp/phpgCCPX8" ]]> However, you would instead see something like this: This is due to the fact that since register_globals is turned on, $testfile already exists in the global scope when extract is called. And since EXTR_SKIP is specified, $testfile is not overwritten with the contents of the $_FILES array so $testfile remains a string. Because strings may be accessed using array syntax and the non-numeric string tmp_name is interpreted as 0, PHP sees $testfile['tmp_name'] as $testfile[0]. &reftitle.seealso; compact