PHP递归函数不返回值 [英] PHP Recursive function not returning value
问题描述
注意:这是一个简化版本来说明这一点。我知道对于图示的代码,可以使用类似print_r(array_map(function($ x){return $ x + 2;},array(2,4,6,8)));但这不会在完整的问题。
并为问题。我有以下代码:
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $' )){
return $ accumulator;
} else {
recursive1(array_slice($ myArray,1),$ accumulator + 1);
}
}
$ testArray = array(3,5,7,9);
print( - >。recursive1($ testArray,10)。< -\\\
);
取得零结果
<$ p $ (输出)
- >< -
添加一点看内部我有
function recursive1($ myArray,$ accumulator){
if(empty ($ myArray)){
print([。$ accumulator。] \\\
); //最终结果
返回$ accumulator;
} else {
print(<。$ accumulator。>); //部分结果
recursive1(array_slice($ myArray,1),$ accumulator + 1);
}
}
$ testArray = array(3,5,7,9);
print( - >。recursive1($ testArray,10)。< -\\\
);
我得到它正在执行它所做的功能,但返回值丢失。(输出)
10 $ 12 $ 13
$ $ b - >< -
所以我应该有
(输出)
- > 14 < -
顺便说一下,我正在使用
> php -version
PHP 5.5。 30(cli)(构建时间:2015年10月23日17:21:45)
版权所有(c)1997-2015 The PHP Group
Zend Engine v2.5.0 Copyright(c)1998-2015 Zend Technologies
我也试着将这个值赋给一个变量(在函数之外)无效。 p>
有什么想法? : - )
您应该拥有这个:
else {
print(<。$ accumulator。>); //部分结果
返回recursive1(array_slice($ myArray,1),$ accumulator + 1);
$ / code>
没有 return
声明,您的最终结果永远不会返回。
Am I missing something? In trying to implement an algorithm I can't obtain a return value for a function. Originally trying to return an array I've encountered simple types won't work as well.
NOTE: This is a simplified version to illustrate the point. I'm aware that for the illustrated code one could use something like print_r(array_map(function($x){return $x+2;}, array(2, 4, 6, 8))); but this won't do in the full problem.
And for the question. I have the following code:
function recursive1($myArray, $accumulator){
if(empty($myArray)){
return $accumulator;
} else {
recursive1(array_slice($myArray, 1), $accumulator+1);
}
}
$testArray = array(3, 5, 7, 9);
print("->".recursive1($testArray,10)."<-\n");
Getting nil as a result
(output)
-><-
Adding a little to see the internals I have
function recursive1($myArray, $accumulator){
if(empty($myArray)){
print("[".$accumulator."]\n"); // End result
return $accumulator;
} else {
print("<".$accumulator.">"); // partial results
recursive1(array_slice($myArray, 1), $accumulator+1);
}
}
$testArray = array(3, 5, 7, 9);
print("->".recursive1($testArray,10)."<-\n");
I get that the function it's doing what it suppose to do but the return value is lost.
(output)
<10><11><12><13>[14]
-><-
So I should have
(output)
->14<-
By the way I'm using
>php -version
PHP 5.5.30 (cli) (built: Oct 23 2015 17:21:45)
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.5.0 Copyright (c) 1998-2015 Zend Technologies
I've also tried to assign the value to a variable (outside the function) to no avail.
Any ideas? :-)
You should have this:
else {
print("<".$accumulator.">"); // partial results
return recursive1(array_slice($myArray, 1), $accumulator+1);
}
Without the return
statement, your final result is never returned.
这篇关于PHP递归函数不返回值的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!