如何循环数组并有条件地更新嵌套值

Question

I have two arrays like:

array (size=4)
 0 => string '5' (length=1)
 1 => string '4' (length=1)
 2 => string '2' (length=1)
 3 => string '2' (length=1)
 3 => string '8' (length=1)

and one array more that I load from an XML file:

object(SimpleXMLElement)[1]
public 'book' => 
array (size=101)
  0 => 
    object(SimpleXMLElement)[2]
      public 'id' => string '1' (length=1)
      public 'title' => string 'p' (length=1)
  1 => 
    object(SimpleXMLElement)[3]
      public 'id' => string '2' (length=1)
      public 'title' => string 'pp' (length=2)
  2 => 
    object(SimpleXMLElement)[4]
      public 'id' => string '3' (length=1)
      public 'title' => string 'pen' (length=3)
  3 => 
    object(SimpleXMLElement)[5]
      public 'id' => string '4' (length=1)
      public 'title' => string 'lapton' (length=6)
      ......
      ......
  101 => 
    object(SimpleXMLElement)[103]
      public 'id' => string '101' (length=1)
      public 'title' => string 'title' (length=5)

I want to compare each value of key id of second array with key of first array for each value. When it's the same, I want to update value of key title of second array.

Answer 1

Try this for now

foreach($array1 as $arr1 => $val1){
  foreach($array2 as $arr2 =>$val2){
    if($arr1==$arr2){
        $val2['title']='update value';
    }    
  }
}