---
page_title: length function reference
description: The `length` function determines the length of a collection or string. Learn how to use the `length` function in Packer templates.
---

# `length` Function

`length` determines the length of a given list, map, or string.

If given a list or map, the result is the number of elements in that collection.
If given a string, the result is the number of characters in the string.

## Examples

```shell-session
> length([])
0
> length(["a", "b"])
2
> length({"a" = "b"})
1
> length("hello")
5
```

When given a string, the result is the number of characters, rather than the
number of bytes or Unicode sequences that form them:

```shell-session
> length("👾🕹️")
2
```

A "character" is a _grapheme cluster_, as defined by
[Unicode Standard Annex #29](http://unicode.org/reports/tr29/). Note that
remote APIs may have a different definition of "character" for the purpose of
length limits on string arguments; a Packer provider is responsible for
translating Packer's string representation into that used by its respective
remote system and applying any additional validation rules to it.
