# Piping operator \<| not documented?

**URL:** <https://discourse.julialang.org/t/piping-operator-not-documented/65666>\
**Category:** New to Julia\
**Tags:** question\
**Created:** [August 2, 2021, 9:05am UTC](https://discourse.julialang.org/t/piping-operator-not-documented/65666 "2021-08-02T09:05:45Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![hobbymarks](https://avatars.discourse-cdn.com/v4/letter/h/6de8d8/32.png) [@hobbymarks](https://discourse.julialang.org/u/hobbymarks)\
**Post date:** [August 2, 2021, 9:05am UTC](https://discourse.julialang.org/t/piping-operator-not-documented/65666/1 "2021-08-02T09:05:45Z")

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I am using Julia 1.6.1 and in help mode can not find \<| documentation but can find .\<| documentation and also can find \<| in .\<| documentaion.  
The details as following:

* * *

➜ julia  
\_  
\_ \_ _(_)\_ | Documentation: [https://docs.julialang.org](https://docs.julialang.org)  
(_) | (_) (_) |  
\_ \_ | | \_\_ \_ | Type “?” for help, “]?” for Pkg help.  
| | | | | | |/ ` | |  
| | || | | | (_| | | Version 1.6.1 (2021-04-23)  
_/ |\ __‘_|_|_|\__ ’\_| |  
|\_\_/ |

help?\> \<|  
search:

No documentation found.

Binding \<| does not exist.

help?\> .\<|  
search:

x .\<| y is akin to broadcast(\<|, x, y). See broadcast.

* * *

![can_not_find_documentation_20210802](https://global.discourse-cdn.com/julialang/original/3X/9/1/912b78072731d88ba5ccfc40b05bd4efdb116f75.png)

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<div class="post-metadata">

**Author:** ![ptoche](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ptoche/32/23554_2.png) [@ptoche](https://discourse.julialang.org/u/ptoche)\
**Post date:** [August 2, 2021, 9:17am UTC](https://discourse.julialang.org/t/piping-operator-not-documented/65666/2 "2021-08-02T09:17:36Z")

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`|>` is documented

 ![help](https://global.discourse-cdn.com/julialang/original/3X/0/a/0a2b642d8a8847b0640a275dc19baf86ece3aae2.png)

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<div class="post-metadata">

**Author:** ![nilshg](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nilshg/32/2283_2.png) [@nilshg](https://discourse.julialang.org/u/nilshg)\
**Post date:** [August 2, 2021, 9:22am UTC](https://discourse.julialang.org/t/piping-operator-not-documented/65666/4 "2021-08-02T09:22:02Z")

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What is `<|`? I get

```julia
julia> <|
ERROR: UndefVarError: <| not defined

```

and, as you show, when searching the help it does say the binding doesn’t exist (because apparently it doesn’t in a fresh Julia session)

What you’re showing in regards to `.<|` is just some auto-generated documentation for a generic infix operator, e.g. picking some other random undefined operator:

```julia
help?> .⟑
".⟑" can be typed by .\wedgedot<tab>

search:

  x .⟑ y is akin to broadcast(⟑, x, y). See broadcast.

julia> ∧
ERROR: UndefVarError: ∧ not defined

```

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<div class="post-metadata">

**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [August 2, 2021, 9:25am UTC](https://discourse.julialang.org/t/piping-operator-not-documented/65666/5 "2021-08-02T09:25:33Z")

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The docs for broadcasting via a dot are generated - they’re the same for all dotted operators (or rather, anything with a leading dot leads to those docs). The text of the docs are generated based on what follows the dot.

`<|` is not an operator exported by julia.

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<div class="post-metadata">

**Author:** ![hobbymarks](https://avatars.discourse-cdn.com/v4/letter/h/6de8d8/32.png) [@hobbymarks](https://discourse.julialang.org/u/hobbymarks)\
**Post date:** [August 4, 2021, 7:58am UTC](https://discourse.julialang.org/t/piping-operator-not-documented/65666/6 "2021-08-04T07:58:11Z")

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\<|  
not |\>

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**Author:** ![jling](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jling/32/212909_2.png) [@jling](https://discourse.julialang.org/u/jling)\
**Post date:** [August 4, 2021, 8:21am UTC](https://discourse.julialang.org/t/piping-operator-not-documented/65666/7 "2021-08-04T08:21:38Z")

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`<|` is not a thing in Julia (it gets parsed as an operator, like `⊗`, but Julia’s base doesn’t define it to do anything at all)