Supported Operations for Lists

You can perform the following kinds of operations on lists.

Insert

Insert elements expr1 , ..., exprn between the (i–1)-th and i-th element of the list.

lst = [lst(0:i-1), expr1,..., exprn, lst(i:*)]

Append

Append elements expr1, ..., exprn after the last element in the list.

lst = [lst, expr1,..., exprn]

Prepend

Prepend elements expr1, ..., exprn before the first element in the list.

lst = [expr1,...,exprn, lst]

Replace

Replace elements between element start and element end with the elements expr1, ..., exprn .

lst = [lst(0:start), expr1,...exprn, lst(end:*)]

Delete

Delete elements between element start and element end.

lst = [lst(0:start), lst(end:*)]

Create Sublists

The method for creating sublists is the same as creating subarrays. For example:

; Create a sublist from a specific range of elements.

sublist = lst(from:to)

; Create a sublist from a specified element to the last element.

toend   = lst(from:*)

; Create a sublist from the first element to a specified element.

startto = lst(0:to)

; Create a sublist containing specified elements only.

sublist = lst([0,2,5])

Enumeration

Lists can be referenced in loops just like other kinds of arrays:

FOR i = 0, N_ELEMENTS(lst) - 1 do BEGIN

; do something with the variable

lst(i) = lst(i) + 1

ENDFOR