Look in the help for slices...
This flexibility allows you to use slices to resize or copy arrays. For example:
Local a[200] 'initialize a[] to 200 elements
a=a[50..150] 'extract middle 100 elements of a[]
a=a[..50] 'extract first 50 elements of a[]
a=a[25..] 'extract elements starting from index 25 of a[]
a=a[..] 'copy all elements of a[]
a=a[..200] 'resize a[] to 200 elements