| ActiveTcl User Guide |

## Tcl/Tk Documentation > TclCmd > lappend

### Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl Library | Tk Library

### NAME

lappend - Append list elements onto a variable

### SYNOPSIS

lappend varName ?value value value ...?

### DESCRIPTION

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.

### EXAMPLE

Using lappend to build up a list of numbers.

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

### SEE ALSO

list, lindex, linsert, llength, lset, lsort, lrange

### KEYWORDS

append, element, list, variable
Copyright © 1995-1997 Roger E. Critchlow Jr. Copyright © 1993 The Regents of the University of California. Copyright © 1994-1996 Sun Microsystems, Inc. Copyright © 2001 Kevin B. Kenny <kennykb(at)acm.org>. All rights reserved.