Question

我有多个包含mathml（xml）元素的数组。

例如我的arraylist：

b'
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我希望所有数组都以Array ( [0] => <mi>x</mi><mo>=</mo><mfrac><mrow><mo>-</mo><mi>b</mi> <mo>±</mo><msqrt><msup><mi>b</mi><mn>2</mn></msup><mo>-</mo><mn>4</mn><mi>a</mi><mi>c</mi></msqrt></mrow><mrow><mn>2</mn><mi>a</mi></mrow></mfrac> [1] => <mi>x</mi><mo>+</mo><mn>2</mn><mo>=</mo><mn>3</mn> [2] => <mfrac><mrow><mn>2</mn><mi>x</mi><mo>+</mo><mn>2</mn></mrow><mn>3</mn></mfrac><mo>-</mo><mn>3</mn><mo>=</mo><mn>2</mn> [3] => <mo>-</mo><mn>3</mn><mo>+</mo><mn>2</mn><mo>=</mo><mi>x</mi> )开头，但如果它以<mo>开头，则它就像数组[3]一样好。

例如我想要的预期输出

<mo>

如您所见，所有数组都以Array ( [0] =><mo>+</mo><mi>x</mi><mo>=</mo><mfrac><mrow><mo>-</mo><mi>b</mi><mo>±</mo><msqrt><msup><mi>b</mi><mn>2</mn></msup><mo>-</mo><mn>4</mn><mi>a</mi><mi>c</mi></msqrt></mrow><mrow><mn>2</mn><mi>a</mi></mrow></mfrac> [1] =><mo>+</mo><mi>x</mi><mo>+</mo><mn>2</mn><mo>=</mo><mn>3</mn> [2] =><mo>+</mo><mfrac><mrow><mn>2</mn><mi>x</mi><mo>+</mo><mn>2</mn></mrow><mn>3</mn></mfrac><mo>-</mo><mn>3</mn><mo>=</mo><mn>2</mn> [3] =><mo>-</mo><mn>3</mn><mo>+</mo><mn>2</mn><mo>=</mo><mi>x</mi> )开头。

以下是我目前添加它的代码：

<mo>

Answer 1

如果你的代码存在问题，那就很多，所以我刚刚写了一些新东西......

$result = ["<mo>+</mo><mi>x</mi><mo>=</mo><mfrac><mrow><mo>-</mo><mi>b</mi><mo>±</mo><msqrt><msup><mi>b</mi><mn>2</mn></msup><mo>-</mo><mn>4</mn><mi>a</mi><mi>c</mi></msqrt></mrow><mrow><mn>2</mn><mi>a</mi></mrow></mfrac>",
    "<mo>+</mo><mi>x</mi><mo>+</mo><mn>2</mn><mo>=</mo><mn>3</mn>",
    "<mfrac><mrow><mn>2</mn><mi>x</mi><mo>+</mo><mn>2</mn></mrow><mn>3</mn></mfrac><mo>-</mo><mn>3</mn><mo>=</mo><mn>2</mn>",
    "<mo>-</mo><mn>3</mn><mo>+</mo><mn>2</mn><mo>=</mo><mi>x</mi>"
    ];
$arr_result=[];

for ($i=0; $i < count($result) ; $i++) {
    if (substr($result[$i],0,4)!="<mo>") {
        $arr_result[]= "<mo>+</mo>".$result[$i];
    }
    else    {
        $arr_result[]= $result[$i];
    }

}
print_r($arr_result);

这一次只是遍历每一行，检查<mo>的前4个字符，如果它不存在则将它们添加到新值中。

输出是......

Array
(
    [0] => <mo>+</mo><mi>x</mi><mo>=</mo><mfrac><mrow><mo>-</mo><mi>b</mi><mo>±</mo><msqrt><msup><mi>b</mi><mn>2</mn></msup><mo>-</mo><mn>4</mn><mi>a</mi><mi>c</mi></msqrt></mrow><mrow><mn>2</mn><mi>a</mi></mrow></mfrac>
    [1] => <mo>+</mo><mi>x</mi><mo>+</mo><mn>2</mn><mo>=</mo><mn>3</mn>
    [2] => <mo>+</mo><mfrac><mrow><mn>2</mn><mi>x</mi><mo>+</mo><mn>2</mn></mrow><mn>3</mn></mfrac><mo>-</mo><mn>3</mn><mo>=</mo><mn>2</mn>
    [3] => <mo>-</mo><mn>3</mn><mo>+</mo><mn>2</mn><mo>=</mo><mi>x</mi>
)

Answer 2

您可以尝试在for循环中执行类似的操作。 strpos将返回您正在搜索的字符串中存在的字符串的位置。因此，在这种情况下，如果字符串以“”开头，则返回0。

$your_string = "<mi>x</mi><mo>+</mo><mn>2</mn><mo>=</mo><mn>3</mn>";
$searching_tag = "<mo>";

$pos = strpos($your_string, $searching_tag);

if($pos === 0)
{
   //string starts with "<mo>"
}
else
{
   //string doesn't start with "<mo>"
}

如何使用php将xml子项添加到数组的第一个索引

2 个答案: