Shortest average

Code Golf

array-manipulation add tag

Adám

# Goal
Given a non-empty list `L` of numbers, compute the arithmetic mean average, that is 
$$
\frac1N\sum_{i=1}^{N}L_i
$$

The goal of this competition is to achieve the shortest code.

## Special rules
- Expressions/snippets that assume the variable `L` to exist are allowed for the purposes of this challenge.

## Example cases
Here are a few test cases that cover both simple cases and any edge cases:

| Input                 | Output                 | Notes  |
|-----------------------|------------------------|--------|
| `[3,1,4,1,5]` | `2.8` |        |
| `[3,3,3,3]`         | `3`          | All same |
| `[7]`                  | `7`                   | Single  |

[Jelly](https://github.com/DennisMitchell/jelly), 2 bytes

Anonymous 1385

[CJam](https://sourceforge.net/p/cjam), 7 bytes

EsolangingFruit

Python 3 Python 2, ~~24~~ 19* bytes

Rahul Verma

[Nim](http://nim-lang.org/), 24 bytes

xigoi

Kotlin [Kotlin](https://kotlinlang.org), 12 bytes

ajc2

[Ruby](https://www.ruby-lang.org/), 31 bytes

razetime

[Uiua](https://www.uiua.org/)[^SBCS^](https://tinyurl.com/Uiua-SBCS-Oct-06), 5 bytes

Europe2048

Top Answer

Anonymous 1385

# [Jelly], 2 bytes
Jelly has a built-in.

    Æm

[Try it online!][TIO-kc3glnzp]

[Jelly]: https://github.com/DennisMitchell/jelly
[TIO-kc3glnzp]: https://tio.run/##y0rNyan8//9wW@7///@jjXUMdUyA2DQWAA "Jelly – Try It Online"

# [Jelly], 3 bytes

    S÷L

[Try it online!][TIO-kc3gkalg]

[Jelly]: https://github.com/DennisMitchell/jelly
[TIO-kc3gkalg]: https://tio.run/##y0rNyan8/z/48Haf////RxvrGOqYALFpLAA "Jelly – Try It Online"

Answer #2

EsolangingFruit

# [CJam], 7 bytes

    L1bL,d/

[Try it online!][TIO-kauougkt]

[CJam]: https://sourceforge.net/p/cjam
[TIO-kauougkt]: https://tio.run/##S85KzP1f6KdfXWflY/3fxzDJRydF/3@tasL/aGMFQwUTIDaN5QKywRDIMo8FAA "CJam – Try It Online"

Answer #3 Python 3

Rahul Verma

# Python 2, ~~24~~ 19* bytes
    print sum(l)/len(l)
[Try it online!](https://tio.run/##K6gsycjPM/qfYxttqGOkYxz7v6AoM69Eobg0VyNHUz8nNQ9I/f8PAA) 

\* 5 bytes reduced by Adam

Answer #4

xigoi

# [Nim], 24 bytes

    import stats
    echo L.mean

[Try it online!][TIO-khp2qh44]

[Nim]: http://nim-lang.org/
[TIO-khp2qh44]: https://tio.run/##y8vM/Z@TWqLgo2CrEG2sY6hjAsSmsf8zcwvyi0oUiksSS4q5UpMz8hV89HJTE/P@/wcA "Nim – Try It Online"

Answer #5 Kotlin

ajc2

# [Kotlin], 12 bytes

    {sum()/size}

[Try it online!][TIO-kel0lqdl]

[Kotlin]: https://kotlinlang.org
[TIO-kel0lqdl]: https://tio.run/##JY6xDoMwEEN3vsJiugylartFBZaObP2CVE3RqSEgkjAU8e3pITb77Hvyd4yOfV6Mg1l6jY5DvD/G9HK2qUjh1OBwqPMa0kDqHPhnt/xJHoNhL521AHaAk1/UoNmad8feStRqlKWqwuQ4UgmRg5noGWf2vdZxPNhKAJOcIu2ISoaQUsWWL7ji9gc "Kotlin – Try It Online"

Answer #6

razetime

# [Ruby], 31 bytes



    ->a{a.inject(:+)/a.length.to_f}

[Try it online!][TIO-keb92rjh]

[Ruby]: https://www.ruby-lang.org/
[TIO-keb92rjh]: https://tio.run/##KypNqvyfZvtf1y6xOlEvMy8rNblEw0pbUz9RLyc1L70kQ68kPz6t9n@BQppCdLShjpGOcWwsF4RnDmcZ6xgjiRvrGOqYALFpbOx/AA "Ruby – Try It Online"

Answer #7

Europe2048

# [Uiua](https://www.uiua.org/)[^SBCS^](https://tinyurl.com/Uiua-SBCS-Oct-06), 5 bytes
	÷⊃⧻/+
[Try it here!](https://www.uiua.org/pad?src=0_13_0-dev_2__RiDihpAgw7fiioPip7svKwpGIDNfMV80XzFfNQpGIDNfM18zXzMKRiDCpDcK)

## Explanation
```
÷⊃⧻/+
 ⊃    Return both the...
   /+ sum
  ⧻   and the length
 ⊃    ...of the input
÷     Divide
```

7 Answers