incr

Increment in $increment an item or all array items (default increment is 1)

<obj> the objarray to be modified

<increment> usually an integer value (1 by default). If the array is of type float or double then increment can be also a real number to be added.

<index> optional integer (starting from 0) to increment only the value of the array at this index

Warning: the values of <obj> itself are modified, without creating another copy of the object