Problems with referencing when iterating through arrays in PHP

Today when using foreach to iterate through an array, I find that there is a problem when using &:

$arr = array (' id ' = ' = ',    ' error ' = ' AA '),    array (' id ' = = = ', ' error ' = ' BB '), "101"); foreach ($arr A S & $value) {    if ($value [' id '] = = 101) $value [' error '] = ' test ';} Var_dump ($arr); foreach ($arr as $value) {}var_dump ($arr);

　　

The manual was later found to be the result of the use of references during traversal, and when the second iteration of the group, the pointer of the array is $value to the element at the end of the array, and when the value is re-assigned $value the element at the end of the pointed array is modified.
The workaround is to $value unset () off after the first traversal is complete.

Problems with referencing when iterating through arrays in PHP