join manual page - Built-In Commands

## Tcl/Tk Documentation > Tcl Commands, version 8.6.18 > join

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### 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, lappend, split

### KEYWORDS

element, join, list, separator
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