array_combine为什么不返回数组？

Question

当我尝试打印从该函数返回的数组时，我得到一个空白屏幕。

我的阵列$terms和$definitions都是相同的长度，他们存在之前和之后我呼吁make_associative_array()。

function make_associative_array() { 
    return array_combine($terms, $definitions); 
} 

$c = make_associative_array(); 
print_r($c); 

$方面：

Array ( 
    [0] => Nock (verb) [1] => End [2] => Serving [3] => Nock (noun) 
) 

$定义：

Array ( 
    [0] => To place an arrow against the string prior to shooting. [1] => A group of arrows shot during a tournament. Usually 6. [2] => Thread wound around a bow string to protect the string. [3] => A notch at the rear of an arrow. The bow string is placed in the nock. 
) 

我使用PHP 27年6月5日

Answer 1

在你的情况 - array_combine回报NULL，因为这两个$terms & $definitions一个在make_associative_array的范围内重新为null。

您可以使它们的全球：

function make_associative_array() { 
    global $terms, $definitions; 
    return array_combine($terms, $definitions); 
} 

或者将它们传递给函数：

function make_associative_array($terms, $definitions) { 
    return array_combine($terms, $definitions); 
} 
$c = make_associative_array($terms, $definitions); 

反正 - 我真的建议你打开错误：
http://sandbox.onlinephpfunctions.com/code/40cfd2d197aebd4d935c793c1ea662cab50ce8b1

Answer 2

您必须将参数传递给功能

<?php 
    function make_associative_array($terms,$definitions) { 

     return array_combine($terms, $definitions); 
    } 

    $terms=Array (0 => 'Nock (verb)', 1 => 'End', 2=> 'Serving', 3=> 'Nock (noun) ' 
    ); 

    $definitions=Array ( 
     0 => 'To place an arrow against the string prior to shooting.' ,1 => 'A group of arrows shot during a tournament. Usually 6.', 2 => 'Thread wound around a bow string to protect the string.' ,3=> 'A notch at the rear of an arrow. The bow string is placed in the nock.' 
    ); 

    $c = make_associative_array($terms,$definitions); 
    echo "<pre>"; 
    print_r($c); 

输出将是

Array 
(
    [Nock (verb)] => To place an arrow against the string prior to shooting. 
    [End] => A group of arrows shot during a tournament. Usually 6. 
    [Serving] => Thread wound around a bow string to protect the string. 
    [Nock (noun) ] => A notch at the rear of an arrow. The bow string is placed in the nock. 
)