php 数组未定义偏移量：0 -- 在第 55 行错误答案

【问题标题】：Php array Undefined offset: 0 -- at line 55 errorphp 数组未定义偏移量：0 -- 在第 55 行错误
【发布时间】：2018-06-02 11:36:12
【问题描述】：

我正在尝试将 simplexmlload 字符串转换为数组，以便输出数组值。但是当我尝试输出数组值时出现此错误：

E_NOTICE : type 8 -- Undefined offset: 0 -- at line 55

错误出现在这行代码：echo $array[0];

这里是完整的代码：

<!DOCTYPE html>
<html>
<body>

<?php
$note=<<<XML
<Projects_Detail>
    <Mr-Imran>
        <projectBudget>125000</projectBudget>
    <EmpNo>E100</EmpNo>
    <DeptName>IT</DeptName>
    <HourlyRate>625</HourlyRate>
    </Mr-Imran>

    <Mr-Imran>
        <projectBudget>120000</projectBudget>
    <EmpNo>E101</EmpNo>
    <DeptName>Database</DeptName>
    <HourlyRate>500</HourlyRate>
    </Mr-Imran>

    <Mr-Imran>
        <projectBudget>135000</projectBudget>
    <EmpNo>E102</EmpNo>
    <DeptName>IT</DeptName>
    <HourlyRate>550</HourlyRate>
    </Mr-Imran>

    <Mr-Imran>
        <projectBudget>115000</projectBudget>
    <EmpNo>E103</EmpNo>
    <DeptName>Testing</DeptName>
    <HourlyRate>400</HourlyRate>
    </Mr-Imran>
    <Mr-Imran>
        <projectBudget>150000</projectBudget>
    <EmpNo>E110</EmpNo>
    <DeptName>Database</DeptName>
    <HourlyRate>375</HourlyRate>
    </Mr-Imran>
    <Mr-Imran>
        <projectBudget>140000</projectBudget>
    <EmpNo>E112</EmpNo>
    <DeptName>Testing</DeptName>
    <HourlyRate>425</HourlyRate>
    </Mr-Imran>
</Projects_Detail>

XML;

$xml=simplexml_load_string($note);
$array =  (array) $xml;
print_r(array_values($array));

echo $array[0];
?>

【问题讨论】：

PHP: "Notice: Undefined variable", "Notice: Undefined index", and "Notice: Undefined offset"的可能重复
您应该研究如何处理 SimpleXML，而不是仅仅将其转换为数组并希望。
你希望得到什么样的输出？

标签： php html arrays xml

【解决方案1】：

你可以使用SimpleXMLElement::children()方法：

<?php
$note=<<<XML
<Projects_Detail>
    <Mr-Imran>
        <projectBudget>125000</projectBudget>
    <EmpNo>E100</EmpNo>
    <DeptName>IT</DeptName>
    <HourlyRate>625</HourlyRate>
    </Mr-Imran>

    <Mr-Imran>
        <projectBudget>120000</projectBudget>
    <EmpNo>E101</EmpNo>
    <DeptName>Database</DeptName>
    <HourlyRate>500</HourlyRate>
    </Mr-Imran>

    <Mr-Imran>
        <projectBudget>135000</projectBudget>
    <EmpNo>E102</EmpNo>
    <DeptName>IT</DeptName>
    <HourlyRate>550</HourlyRate>
    </Mr-Imran>

    <Mr-Imran>
        <projectBudget>115000</projectBudget>
    <EmpNo>E103</EmpNo>
    <DeptName>Testing</DeptName>
    <HourlyRate>400</HourlyRate>
    </Mr-Imran>
    <Mr-Imran>
        <projectBudget>150000</projectBudget>
    <EmpNo>E110</EmpNo>
    <DeptName>Database</DeptName>
    <HourlyRate>375</HourlyRate>
    </Mr-Imran>
    <Mr-Imran>
        <projectBudget>140000</projectBudget>
    <EmpNo>E112</EmpNo>
    <DeptName>Testing</DeptName>
    <HourlyRate>425</HourlyRate>
    </Mr-Imran>
</Projects_Detail>

XML;

$xml = simplexml_load_string($note);
$children = $xml->children();

foreach($children as $child) {
    print_r($child);
    echo "<br/>";
}

您将收到以下输出：

SimpleXMLElement Object ( [projectBudget] => 125000 [EmpNo] => E100 [DeptName] => IT [HourlyRate] => 625 )
SimpleXMLElement Object ( [projectBudget] => 120000 [EmpNo] => E101 [DeptName] => Database [HourlyRate] => 500 )
SimpleXMLElement Object ( [projectBudget] => 135000 [EmpNo] => E102 [DeptName] => IT [HourlyRate] => 550 )
SimpleXMLElement Object ( [projectBudget] => 115000 [EmpNo] => E103 [DeptName] => Testing [HourlyRate] => 400 )
SimpleXMLElement Object ( [projectBudget] => 150000 [EmpNo] => E110 [DeptName] => Database [HourlyRate] => 375 )
SimpleXMLElement Object ( [projectBudget] => 140000 [EmpNo] => E112 [DeptName] => Testing [HourlyRate] => 425 )

通过将foreach 循环替换为upgraded 循环，我们使用array-casting，您可以将XML 数据作为方便的数组：

foreach($children as $child) {
    $childArray = (array)$child;
    print_r($childArray);
    echo "<br/>";
}

会给你以下输出：

Array ( [projectBudget] => 125000 [EmpNo] => E100 [DeptName] => IT [HourlyRate] => 625 )
Array ( [projectBudget] => 120000 [EmpNo] => E101 [DeptName] => Database [HourlyRate] => 500 )
Array ( [projectBudget] => 135000 [EmpNo] => E102 [DeptName] => IT [HourlyRate] => 550 )
Array ( [projectBudget] => 115000 [EmpNo] => E103 [DeptName] => Testing [HourlyRate] => 400 )
Array ( [projectBudget] => 150000 [EmpNo] => E110 [DeptName] => Database [HourlyRate] => 375 )
Array ( [projectBudget] => 140000 [EmpNo] => E112 [DeptName] => Testing [HourlyRate] => 425 )

【讨论】：