FS = ","

Expressions using the operators +, -, /, and % (modulo) can be assigned to variables.

/widget/ { count["widget"]++ }		Count widgets
END      { print count["widget"] }		Print the count

You can use the special for loop to read all the elements of an associative array:

for (item in array)
	process array[item]

The index of the array is available as item, while the value of an element of the array can be referenced as array[item].

You can use the operator in to see if an element exists by testing to see if its index exists (nawk only):

if (index in array)
	...

This sequence tests that array[index] exists, but you cannot use it to test the value of the element referenced by array[index].

You can also delete individual elements of the array using the delete statement (nawk only).