lappend man page

lappend — Append list elements onto a variable


lappend varName ?value value value ...?


This command treats the variable given by varName as a list and appends each of the value arguments to that list as a separate element, with spaces between elements. If varName does not exist, it is created as a list with elements given by the value arguments. Lappend is similar to append except that the values are appended as list elements rather than raw text. This command provides a relatively efficient way to build up large lists. For example, “lappend a $b” is much more efficient than “set a [concat $a [list $b]]” when $a is long.


Using lappend to build up a list of numbers.

% set var 1
% lappend var 2
1 2
% lappend var 3 4 5
1 2 3 4 5

See Also

list(n), lindex(n), linsert(n), llength(n), lset(n), lsort(n), lrange(n)


append, element, list, variable

Referenced By

append(n), dict(n), join(n), lindex(n), linsert(n), list(n), llength(n), lrange(n), lrepeat(n), lreplace(n), lsearch(n), lset(n), lsort(n).

Tcl Tcl Built-In Commands