Php 如何使它提取递增变量，直到变为空？

是否可以将其设置为动态的，这样它就可以一直更改第一个和最后一个数字，直到它变成一个空变量，并在该变量停止时运行下一个函数？

for（$i=0；$i感谢您，它工作得很好，我以前从未使用过“for”函数。现在我将更频繁地使用它。
extract ($wddx_0, EXTR_PREFIX_ALL, "wddx0");
extract ($wddx_1, EXTR_PREFIX_ALL, "wddx1");
extract ($wddx_2, EXTR_PREFIX_ALL, "wddx2");
extract ($wddx_3, EXTR_PREFIX_ALL, "wddx3");
extract ($wddx_4, EXTR_PREFIX_ALL, "wddx4");
extract ($wddx_5, EXTR_PREFIX_ALL, "wddx5");
extract ($wddx_6, EXTR_PREFIX_ALL, "wddx6");
extract ($wddx_7, EXTR_PREFIX_ALL, "wddx7");
extract ($wddx_8, EXTR_PREFIX_ALL, "wddx8");
extract ($wddx_9, EXTR_PREFIX_ALL, "wddx9");
extract ($wddx_10, EXTR_PREFIX_ALL, "wddx10");
extract ($wddx_11, EXTR_PREFIX_ALL, "wddx11");
extract ($wddx_12, EXTR_PREFIX_ALL, "wddx12");
extract ($wddx_13, EXTR_PREFIX_ALL, "wddx13");
extract ($wddx_14, EXTR_PREFIX_ALL, "wddx14");
extract ($wddx_15, EXTR_PREFIX_ALL, "wddx15");
extract ($wddx_16, EXTR_PREFIX_ALL, "wddx16");
extract ($wddx_17, EXTR_PREFIX_ALL, "wddx17");
extract ($wddx_18, EXTR_PREFIX_ALL, "wddx18");
extract ($wddx_19, EXTR_PREFIX_ALL, "wddx19");

for ($i=0; $i<=19; $i++){
    extract(${'wddx_'.$i}, EXTR_PREFIX_ALL, "wddx".$i);
}