PHP 中 extract 同名覆盖

extract()方法会根据一个Array创建相应的变量,并且会覆盖同名变量的值。幸运的是extract()提供了第二个参数,一个标志符。

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 array parameter. You can use this flag on its own or combine it with any other flag by OR’ing the flags.

If flags is not specified, it is assumed to be EXTR_OVERWRITE.

所以解决同名覆盖的一个方法就是使用EXTRA_PREFEX_ALL标志,这样extract()在创建Array对应变量的时候会自动加上第三个参数设置的前缀字符串。eg:

        $name = "wangsijie";
        $person = array('name' => "lnmcc", 'age' => 100);
        extract($person, EXTR_PREFIX_ALL, "person");
        echo "Name: {$name}, Person Name: {$person_name}, Person Age: {$person_age}";