---
name: "lappend"
section: "3tcl"
platform: "linux"
package: "tcl8.6-doc"
version: "8.6.16+dfsg-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/lappend"
---

# lappend(3tcl)

Append list elements onto a variable

```

```

## 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 *value*s 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(3tcl)](/list/3tcl.md), [lindex(3tcl)](/lindex/3tcl.md), [linsert(3tcl)](/linsert/3tcl.md), [llength(3tcl)](/llength/3tcl.md), [lset(3tcl)](/lset/3tcl.md), [lsort(3tcl)](/lsort/3tcl.md), [lrange(3tcl)](/lrange/3tcl.md)

## KEYWORDS

append, element, list, variable