stdlib.core

List

length

Add note

Function length

View source on GitHub

int

length (

list

(

)

Compute the length of a list.Performance note: if you only need to check whether a list is empty, you should rather useList.is_empty, which is much faster than List.length, in particular when your list is stored in
the database.

returns

The number of elements in the list, which is 0 if the list is {nil} or a strictly
positive number otherwise..

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Markdown Syntax Help

You can enter a message using a Markdown-like syntax. Here is a list of all elements recognized.

Paragraph

A group of text isolated by two or more linebreaks will be put in a HTML paragraph <p>.

Titles

You can enter titles using various syntax:

First level title
=================

will create:

First level title

and

Second level title
------------------

will create:

Second level title

You can also create titles by preceding text with as many # as the level of the title, so

#### Title 4

will create:

Title 4

Emphasis

You may want to put emphasis on some words in your texts.

You can do a simple emphasis by surrounding some text with * or _: *text* will give in result *text*.

To put a strong emphasis on something, you can surround it with ** or __: __text__ will give in result text.

You can put *a **strong emphasis** inside a simple one* or __a _simple emphasis_ inside a strong one__.

Lists

You can insert simple bullet lists simply by putting each element in a line starting by a -, a + or a *. Mixing symbols will not create different lists unless there is a blank line in the middle:

- one
- two

* three
+ four

will result in:

three
four

If you want to put a linebreak in your source to avoid very long lines, you can put four spaces or a tabulation at the beginning of your line to keep the content as one list element:

-   one
    two
-   three
    four

will result in:

one two
three four

To insert numbered lists, you can follow the same rules and start your lines with a number followed by a period. The numbers do not have to follow a logical suit to be recognized:

1.  one
    two
3.  three
42. four
444. five

will result in:

one two
three
four
five

Links

You can insert links inside your text in two ways:

some text [Inline-style](https://mlstate.com "MLstate") more text
or
some text [Reference-style][mlstate] some random text
[mlstate]: https://mlstate.com  "MLstate"

In both cases, the title ("MLstate") is optional. The result of the above is:

some text Inline-style more text or some text Reference-style some random text

Note that references are case-sensitive and can be used for several links.

Images

Image insertion uses the same syntax than inserting links preceded by a !:

![HTML5](http://www.w3.org/html/logo/badge/html5-badge-h-solo.png "HTML5")
![HTML5][html5]
[html5]: http://www.w3.org/html/logo/badge/html5-badge-h-solo.png "HTML5"

both result in:

You can use the same reference for a link and an image (referencing the same URL).

Code

There are two ways of inserting code inside your text.

Firstly, you can surround it with `, so `some code` will result in some code.

You can also indent a paragraph with at least four spaces or a tabulation:

    rec fact(x) =
      if x < 1 then 1
      else x * fact(x-1)

will result in:

rec fact(x) =
  if x < 1 then 1
  else x * fact(x-1)

Quote

You can insert a quote in you texts by preceding it with >. You can put a quote inside a quote:

> > An indented quote
> A standard quote

will result in:

An indented quote

A standard quote

Other

You can insert an html line break (<br/>) by putting two spaces at the end of the line. You can insert a horizontal line by writing a line containing only the character - preceded by an empty line (otherwise it would result in a second-level header).

--------------
Some text
with a linebreak

will result in:

Some text with a linebreak

You can enter a message using a Markdown-like syntax.
Here is a list of all elements recognized.

## Paragraph

A group of text isolated by two or more linebreaks will be put
in a HTML paragraph <p>.

## Titles

You can enter titles using various syntax:

    First level title
    =================

will create:

First level title
=================

and

    Second level title
    ------------------

will create:

Second level title
-----------------

You can also create titles by preceding text with as many `#` as the
level of the title, so

    #### Title 4

will create:

#### Title 4

## Emphasis

You may want to put emphasis on some words in your texts.

You can do a *simple emphasis* by surrounding some text with
`*` or `_`: `*text*` will give in result *text*.

To put a **strong emphasis** on something, you can surround it with
`**` or `__`: `__text__` will give in result __text__.

You can put *a **strong emphasis** inside a simple one* or
__a _simple emphasis_ inside a strong one__.

## Lists

You can insert simple bullet lists simply by putting each element in
a line starting by a `-`, a `+` or a `*`. Mixing symbols will not create
different lists unless there is a blank line in the middle:

    - one
    - two

    * three
    + four

will result in:

- one
- two

* three
+ four

If you want to put a linebreak in your source to avoid very long lines, you
can put four spaces or a tabulation at the beginning of your line to keep the
content as one list element:

    -   one
        two
    -   three
        four

will result in:

-   one
    two
-   three
    four

To insert numbered lists, you can follow the same rules and start your lines
with a number followed by a period. The numbers do not have to follow a logical
suit to be recognized:

    1.  one
        two
    3.  three
    42. four
    444. five

will result in:

1.  one
    two
3.  three
42. four
444. five


## Links

You can insert links inside your text in two ways:

    some text [Inline-style](https://mlstate.com "MLstate") more text
    or
    some text [Reference-style][mlstate] some random text
    [mlstate]: https://mlstate.com  "MLstate"

In both cases, the title `("MLstate")` is optional. The result of the above is:

some text [Inline-style](https://mlstate.com "MLstate") more text
or
some text [Reference-style][mlstate] some random text
[mlstate]: https://mlstate.com  "MLstate"

Note that references are case-sensitive and can be used for several links.

## Images

Image insertion uses the same syntax than inserting links preceded by a `!`:

    ![HTML5](http://www.w3.org/html/logo/badge/html5-badge-h-solo.png "HTML5")
    ![HTML5][html5]
    [html5]: http://www.w3.org/html/logo/badge/html5-badge-h-solo.png "HTML5"

both result in:

![HTML5](http://www.w3.org/html/logo/badge/html5-badge-h-solo.png "HTML5")
![HTML5][html5]
[html5]: http://www.w3.org/html/logo/badge/html5-badge-h-solo.png "HTML5"

You can use the same reference for a link and an image (referencing the same URL).

## Code

There are two ways of inserting code inside your text.

Firstly, you can surround it with `\``, so `\`some code\`` will
result in `some code`.

You can also indent a paragraph with at least four spaces or a tabulation:

        rec fact(x) =
          if x < 1 then 1
          else x * fact(x-1)

will result in:

    rec fact(x) =
      if x < 1 then 1
      else x * fact(x-1)

## Quote

You can insert a quote in you texts by preceding it with `>`. You
can put a quote inside a quote:

    > > An indented quote
    > A standard quote

will result in:

> > An indented quote
> A standard quote

## Other

You can insert an html line break (`<br/>`) by putting two spaces at
the end of the line.
You can insert a horizontal line by writing a line containing only
the character `-` preceded by an empty line (otherwise it would result
in a second-level header).

    --------------
    Some text
    with a linebreak


will result in:

--------------
Some text
with a linebreak

This help is written using this syntax. You can switch between the source and the result.

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