lreplace

lreplace(n)                   Tcl Built-In Commands                  lreplace(n)



________________________________________________________________________________

NAME
       lreplace - Replace elements in a list with new elements

SYNOPSIS
       lreplace list first last ?element element ...?
________________________________________________________________________________

DESCRIPTION
       lreplace returns a new list formed by replacing zero or more elements of
       list with the element arguments.  first and last are index values
       specifying the first and last elements of the range to replace.  The
       index values first and last are interpreted the same as index values for
       the command string index, supporting simple index arithmetic and indices
       relative to the end of the list.  0 refers to the first element of the
       list, and end refers to the last element of the list.

       If either first or last is less than zero, it is considered to refer to
       before the first element of the list. This allows lreplace to prepend
       elements to list.  If either first or last indicates a position greater   │
       than the index of the last element of the list, it is treated as if it is │
       an index one greater than the last element. This allows lreplace to       │
       append elements to list.

       If last is less than first, then any specified elements will be inserted
       into the list before the element specified by first with no elements
       being deleted.

       The element arguments specify zero or more new elements to be added to
       the list in place of those that were deleted.  Each element argument will
       become a separate element of the list.  If no element arguments are
       specified, then the elements between first and last are simply deleted.

EXAMPLES
       Replacing an element of a list with another:

              % lreplace {a b c d e} 1 1 foo
              a foo c d e

       Replacing two elements of a list with three:

              % lreplace {a b c d e} 1 2 three more elements
              a three more elements d e

       Deleting the last element from a list in a variable:

              % set var {a b c d e}
              a b c d e
              % set var [lreplace $var end end]
              a b c d

       A procedure to delete a given element from a list:

              proc lremove {listVariable value} {
                  upvar 1 $listVariable var
                  set idx [lsearch -exact $var $value]
                  set var [lreplace $var $idx $idx]
              }

       Appending elements to the list; note that end+2 will initially be treated │
       as if it is 6 here, but both that and 12345 are greater than the index of │
       the final item so they behave identically:                                │

              % set var {a b c d e}                                              │
              a b c d e                                                          │
              % set var [lreplace $var 12345 end+2 f g h i]                      │
              a b c d e f g h i                                                  │

SEE ALSO
       list(n), lappend(n), lindex(n), linsert(n), llength(n), lsearch(n),
       lset(n), lrange(n), lsort(n), string(n)

KEYWORDS
       element, list, replace



Tcl                                    7.4                           lreplace(n)