I have multiple arrays containing mathml(xml) elements.
For example my arraylist:
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>
)
I want all array to start with <mo> but if it starts with <mo> then it's fine like array [3].
For example the expected output I want
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>
)
As you can see all array starts with <mo>.
Below is my current code to add it:
$ress = array();
$arr_result=[];
for ($i=0; $i <= $length ; $i++) {
$ress=$result[$i];
if ($pos = (substr($ress,0,3)!="<mo>")) {
$arr_result[]=array_unshift($ress, "<mo>+</mo>");
}
else{
$arr_result[]=$ress;
}
}
print_r($arr_result);
$result store the array.
There are a lot if issues with the code you have, so I've just written something new...
$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);
This just goes through each line at a time, checking the first 4 chars for <mo> and adds them into the new value if it's not there.
Output is...
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>
)
You could try to do something like this in your for loop. strpos will return the position of the string you are looking for if it does exist in the string you are searching in. So, in this case if the string starts with "" it will return 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>"
}