Scanning Multidimensional Arrays
================================
There is no special `for' statement for scanning a
"multidimensional" array. There cannot be one, because in truth there
are no multidimensional arrays or elements--there is only a
multidimensional _way of accessing_ an array.
However, if your program has an array that is always accessed as
multidimensional, you can get the effect of scanning it by combining
the scanning `for' statement (*note Scanning All Elements of an Array:
Scanning an Array.) with the built-in `split' function (Note:String
Manipulation Functions.). It works in the following
manner:
for (combined in array) {
split(combined, separate, SUBSEP)
...
}
This sets the variable `combined' to each concatenated combined index
in the array, and splits it into the individual indices by breaking it
apart where the value of `SUBSEP' appears. The individual indices then
become the elements of the array `separate'.
Thus, if a value is previously stored in `array[1, "foo"]'; then an
element with index `"1\034foo"' exists in `array'. (Recall that the
default value of `SUBSEP' is the character with code 034.) Sooner or
later, the `for' statement finds that index and does an iteration with
the variable `combined' set to `"1\034foo"'. Then the `split' function
is called as follows:
split("1\034foo", separate, "\034")
The result is to set `separate[1]' to `"1"' and `separate[2]' to
`"foo"'. Presto! The original sequence of separate indices is
recovered.