---
name: join
status: documented
runtime: pp
source: src/runtime/pp/strings/join.rs
---
```{index} single: join; Perl built-in (pp runtime)
```

# join

## Synopsis

```perl
$str = join(',', @array);
$str = join(' ', 'hello', 'world');
$str = join('', @chars);           # no separator
```

## Description

Concatenates a list of values into a single string with a separator.

Takes a separator string followed by a list of values (from a
pushmark-delimited argument list on the stack). The separator is
inserted between each adjacent pair of values. Array arguments are
flattened. Returns the resulting string; an empty string when no
list values are given.

Uses `Cow<str>` for the separator and parts to avoid allocation
when the underlying SVs are already string-typed.

## See also

split, sprintf