PHP

php .=

10.string Operator
    . =  concatenation operator
    .= concatenating assignment operator

php =>

PHP =>
  //The double arrow operator, => 
  //Used as an access mechanism for arrays.
  //The left side will have a corresponding value on the right side in array. 
  //This can be used to set values into a corresponding index of an array. 
  //The index can be a string or number.
$myArray = array(
    0 => 'Red',
    1 => 'Orange',
    2 => 'Yellow',
    3 => 'Green'
);