表 7.1 describes list operators and their JSL syntax.
Operator and Function |
Syntax |
Explanation |
|
---|---|---|---|
|
As List() |
As List(matrix) |
Returns the matrix as a list. A matrix with multiple columns is returned as a list of lists, one list per row. |
= += -= *= /= ++ -- |
Assign() Add To() SubtractTo() MultiplyTo() DivideTo() Post Increment() Post Decrement() |
{list} = {list} {list} += value {list} -= {list} ... |
If the target of an assignment operator is a list and the value to be assigned is a list, then it assigns item by item. The ultimate values in the left list must be L-values (in other words, names capable of being assigned values). Notes: • If you want to test equality of lists, use ==, not =. • JMP does not have pre-increment or pre-decrement operators. Instead, use the Add To() operator, which is (+=), or the Subtract To() operator, which is (-=). |
||= |
Concat To() |
Concat To(list1, list2, ...) |
Inserts the second and subsequent lists at the end of the first list. |
|| |
Concat() |
Concat(list1, list2, ...); |
Returns a copy of the first list with any additional lists inserted at after it. |
|
Eval List() |
Eval List(list) |
Returns a list of the evaluated expressions inside list. See Evaluate Lists. |
|
Insert Into() |
Insert Into(list, x, <i>) |
Inserts a new item (x) into the list at the given position (i). If i is not given, the item is added to the end of the list. This function does change the original list. |
|
Insert() |
list = Insert(list, x, <i>) |
Returns a copy of the list with a new item (x) inserted into the list at the given position (i). If i is not given, the item is added to the end of the list. This function does not change the original list. |
|
Is List() |
Is List(arg) |
Returns true (1) if arg is a classical list (in other words, one that would result from the construction by List(items) or {items}) and returns false (0) otherwise. An empty list is still a list, so IsList({ }) returns true. If miss=., then IsList(miss) returns false, not missing. |
{ } |
List |
List(a, b, c) {a, b, c} |
Constructs a list from a set of items. An item can be any expression, including other lists. Items must be separated by commas. Text should either be enclosed in double quotation marks ( " " ) or stored in a variable and called as that variable. |
|
N Items |
N Items(list) |
Returns the number of elements in the list specified. Can be assigned to a variable. |
|
Remove From() |
Remove From(list, <i>, <n>) |
Deletes n items from the list, starting from the indicated position (i). If n is omitted, the item at i is deleted. If n and i are omitted, the item at the end is removed. This function does change the original list. |
|
Remove() |
Remove(list, <i>, <n>) |
Returns a copy of the list with the n items deleted, starting from the indicated position (i). If n is omitted, the item at i is deleted. If n and i are omitted, the item at the end is removed. This function does not change the original list. |
|
Reverse Into() |
Reverse Into(list) |
Reverses the order of the items in the list. This function does change the original list. |
|
Reverse() |
Reverse(list) |
Returns a copy of the list with the items in reverse order. This function does not change the original list. |
|
Shift Into() |
Shift Into(list, <n>) |
Shifts n items from the front of the list to the end of the list. If n is omitted, the first item is moved to the end of the list. This function does change the original list. |
|
Shift() |
Shift(list, <n>) |
Returns a copy of the list with n items shifted from the front of the list to the end of the list. If n is omitted, the first item is moved to the end of the list. This function does not change the original list. |
|
Sort Ascending() |
Sort Ascending(list) |
Returns a copy of the list sorted in ascending order. This function does not change the original list. |
|
Sort Descending() |
Sort Descending(list) |
Returns a copy of the list sorted in descending order. This function does not change the original list. |
|
Sort List Into() |
Sort List Into(list) |
Sorts the list in ascending order. This function does change the original list. |
|
Sort List() |
Sort List(list) |
Returns a copy of the list sorted in ascending order. This function does not change the original list. |
[ ] |
Subscript() |
list[i] x = list[i] list[i] = value a[b, c] Subscript(a, b, c) |
Subscripts for lists extract the ith item from the list. Subscripts can in turn be lists or matrices. |
|
Substitute() |
Substitute(list, pattExpr1, replExpr1, ...) |
Returns a copy of a string, list, or expression, replacing instances of each pattern expression with the corresponding replacement expression. See Substitute and Substitute Into Functions. |
|
Substitute Into() |
Substitute Into(list, pattExpr1, replExpr1, ...) |
Changes a string, list, or expression, replacing instances of each pattern expression with the corresponding replacement expression. Note: The list or expression must be a variable. See Substitute and Substitute Into Functions. |