---
name: "join"
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/join/3tcl"
---

# join(3tcl)

Create a string by joining together list elements

```

```

## NAME

join - Create a string by joining together list elements

## SYNOPSIS

**join** *list* ?*joinString*?

```

```

## DESCRIPTION

The *list* argument must be a valid Tcl list. This command returns the string formed by joining all of the elements of *list* together with *joinString* separating each adjacent pair of elements. The *joinString* argument defaults to a space character.

## EXAMPLES

Making a comma-separated list:

```
set data {1 2 3 4 5}
join $data ", "
     → 1, 2, 3, 4, 5
```

Using **join** to flatten a list by a single level:

```
set data {1 {2 3} 4 {5 {6 7} 8}}
join $data
     → 1 2 3 4 5 {6 7} 8
```

## SEE ALSO

[list(3tcl)](/list/3tcl.md), [lappend(3tcl)](/lappend/3tcl.md), [split(3tcl)](/split/3tcl.md)

## KEYWORDS

element, join, list, separator