Structure notation

Object.property

You can refer to a property, prop, of an object, obj, as obj.prop. This notation is useful for simple assignments, as in this example:

depts.John="Sales"

Use this notation only when you know the property names (keys) in advance and they are strings, with no special characters, numbers, or spaces. You cannot use the dot notation when the property, or key, is dynamic.

Associative arrays

If you do not know the key name in advance, or it contains spaces, numbers, or special characters, you can use associative array notation. This notation uses structures as arrays with string indexes; for example:

depts["John"]="Sales"
depts[employeeName]="Sales" 

You can use a variable (such as employeeName) as an associative array index. Therefore, you must enclose any literal key names in quotes.

For information on using associative array references containing variables, see Dynamically constructing structure references.