6.3.7  Modifying the elements of a list

The subsop command can be used to modify elements in a list.

• subsop takes two arguments:
  • L, a list.
  • i=value, an index and a new value.
• (In all but Maple mode).

  subsop(L,i=value) returns the list L with the value at index i replaced by value.

• (In Maple mode; the only difference is the order of the arguments).

  subsop(i=value,L) returns the list L with the value at index i replaced by value.

Remark.

If the second argument is i=NULL, then the element at index i is removed from L.

You can also redefine elements (or define new elements, but not remove elements) with :=.

Examples

Input in Xcas mode, the index of the first element is 0:

or:

Input in Xcas mode, the index of the first element is 0:

Input in MuPAD or TI mode, the index of the first element is 1:

or:

When using := to insert an element in a list, the list will be padded with zeros if necessary.

then:

In Maple mode the arguments are permuted and the index of the first element is 1.

or: