Description
int extract (array var_array [, int extract_type [, string prefix]])
This function is used to import variables from an array into the current symbol table. It takes 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.
Extract() checks for colissions with existing variables. The way collisions are treated is determined by 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 new variable with prefix.
- EXTR_PREFIX_ALL
Prefix all variables with prefix.
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 or EXTR_PREFIX_ALL.
Extract() checks each key to see if it constitues a valid variable name, and if it does only then does it proceed to import it.
A possible use for extract is to import into symbol table variables contained in an associative array returned by wddx_deserialize().
Example 1. Extract() example
<?php /* Suppose that $var_array is an array returned from wddx_deserialize */ $size = "large"; $var_array = array ("color" => "blue", "size" => "medium", "shape" => "sphere"); extract ($var_array, EXTR_PREFIX_SAME, "wddx"); print "$color, $size, $shape, $wddx_size\n"; ?> |
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The above example will produce:
blue, large, sphere, medium |
The $size wasn't overwritten, becaus 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 cause $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.
See also: compact().
