关于递归的问题
function getArr($arr='') { for ($i = 0; $i <= 9; $i++) { $arr[] = $i; if (count($arr) < 3) { echo (count($arr)), "|<br/>"; // 这里为什么输出2个2? getArr($arr); // 这里不是开辟新栈吗?新栈的变量$i应该好没有执行$i++ } } return $arr; }$arr = array();echo "<pre class="brush:php;toolbar:false">";print_r(getArr($arr));echo "
上面注释getArr($arr) 这里不是开辟新栈吗?新栈的变量$i应该还没有执行$i++,为什么输出
1|2|2|Array( [0] => 0 [1] => 1 [2] => 2 [3] => 3 [4] => 4 [5] => 5 [6] => 6 [7] => 7 [8] => 8 [9] => 9)
echo (count($arr)), "|
"; 上面这里为什么输出2个2?
回复讨论(解决方案)
这样应该看得清楚些
function getArr($arr='') { printf("传入 %s 大小 %d", print_r($arr, 1), count($arr)); for ($i = 0; $i <= 9; $i++) { $arr[] = $i; if (count($arr) < 3) { echo ' 赋值后 ', (count($arr)), "<br>"; getArr($arr); } } return $arr; } $arr = array();getArr($arr);
传入 Array ( ) 大小 0 赋值后 1传入 Array ( [0] => 0 ) 大小 1 赋值后 2传入 Array ( [0] => 0 [1] => 0 ) 大小 2 赋值后 2传入 Array ( [0] => 0 [1] => 1 ) 大小 2
所以递归只是干扰视线
这样应该看得清楚些
function getArr($arr='') { printf("传入 %s 大小 %d", print_r($arr, 1), count($arr)); for ($i = 0; $i <= 9; $i++) { $arr[] = $i; if (count($arr) < 3) { echo ' 赋值后 ', (count($arr)), "<br>"; getArr($arr); } } return $arr; } $arr = array();getArr($arr);
传入 Array ( ) 大小 0 赋值后 1传入 Array ( [0] => 0 ) 大小 1 赋值后 2传入 Array ( [0] => 0 [1] => 0 ) 大小 2 赋值后 2传入 Array ( [0] => 0 [1] => 1 ) 大小 2
所以递归只是干扰视线
非常感谢。

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