(PHP 3>= 3.0.7, PHP 4 >= 4.0.0)
extract -- Import variables into the current symbol table from an arrayThis function is used to import variables from an array into the current symbol table. It takes an associative array var_array and 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.
Note: Since version 4.0.5 this function returns the number of variables extracted.
Note: EXTR_IF_EXISTS and EXTR_PREFIX_IF_EXISTS was introduced in version 4.2.0. variables extracted.
extract() checks each key to see whether it constitutes a valid variable name and also for collisions with existing variables in the symbol table. The way invalid/numeric keys and collisions are treated is determined by extract_type. It can be one of the following values:
If there is a collision, overwrite the existing variable.
If there is a collision, don't overwrite the existing variable.
If there is a collision, prefix the variable name with prefix.
Prefix all variable names with prefix. Since PHP 4.0.5 this includes numeric ones as well.
Only prefix invalid/numeric variable names with prefix. This flag was added in PHP 4.0.5.
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. This flag was added in PHP 4.2.0.
Only create prefixed variable names if the non-prefixed version of the same variable exists in the current symbol table. This flag was added in PHP 4.2.0.
If extract_type is not specified, it is assumed to be EXTR_OVERWRITE.
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.
extract() returns the number of variables successfully imported into the symbol table.
A possible use for extract is to import into the symbol table variables contained in an associative array returned by wddx_deserialize().
The above example will produce:
blue, large, sphere, medium |
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.
You must use an associative array, a numerically indexed array will not produce results unless you use EXTR_PREFIX_ALL or EXTR_PREFIX_INVALID.
See also compact().