How to group a collection in Liquid? - jekyll

I have a Jekyll app (using Liquid) and I'd like to know how to, in Liquid, group a collection of items into a small subset of collections.
For instance, pretend I have this array:
fruits = ['apples', 'oranges', 'bananas', 'pears', 'grapes']
What I'd really like to do, in the Liquid page, is get this:
fruit_groups = [['apples', 'oranges'], ['bananas', 'pears'], ['grapes', null]]
For example, Ruby on Rails can do this with their .group_by method attached to enumerables.
Can I do this in Liquid?
Use case: I have a big collection of items, but I need to convert them into columns of <ul> elements. So, if I have three columns, I need to get three sub-collections.
Thanks!

This doesn't answer your question directly, but I'm not sure that you'd want to do what you're describing (and I'm pretty sure you can't) - Liquid is a templating system, not a fully fledged programming language. I suspect that you'll be able to achieve your end goal using some of the for loop and cycle features: http://code.google.com/p/liquid-markup/wiki/UsingLiquidTemplates
eg:
<ul>
{% for fruit in fruits %}
{% capture pattern %}{% cycle 'odd_class', 'even_class' %}{% endcapture %}
<li class={{ pattern }}>{{ fruit }}</li>
{% endfor %}
</ul>
or
<ul class="odd">
{% for fruit in fruits %}
{% capture pattern %}{% cycle 'odd', 'even' %}{% endcapture %}
{% if pattern == 'odd' %}
<li>{{ fruit }}</li>
{% endif%}
{% endfor %}
</ul>
<ul class="even">
{% for item in fruits %}
{% capture pattern %}{% cycle 'odd', 'even' %}{% endcapture %}
{% if pattern == 'even' %}
<li>{{ fruit }}</li>
{% endif%}
{% endfor %}
</ul>
If you have three columns, you'd just have three steps in your cycle, and three directions to go in your if statement.
If all that fails, you could write a plugin (in Ruby) that will restructure your data before it ever hits the template layer, but I suspect that would be overkill.

Related

Jekyll nested include with for loop

I'd like to use a {% for %} loop in an included file, to avoid repeating logic to create the loop array (it's an assign with multiple where_exps).
But I'd like to use different content depending on where I include the loop, so sometimes I will do this:
{% for i in a %}
<li>{{ i.name }}</li>
{% endfor %}
and sometimes:
{% for i in a %}
<loc>{{ i.url }}</loc>
{% endfor %}
How can I achieve this? So far I have to put each of the inner contents in their own template, so I would have files like below, but I'd like to avoid the extra template files, and just keep that content in the appropriate main file:
html_template.html:
<li>{{ i.name }}</li>
xml_template.xml:
<loc>{{ i.url }}</loc>
page_loop.html:
{% assign a = "logic I don't want to repeat" %}
{% for i in a %}
{% include {{ include.inner_template }} %}
{% endfor %}
html_main.html:
{% include page_loop.html inner_template="html_template.html" %}
xml_main.xml:
{% include page_loop.html inner_template="xml_template.xml" %}
It would probably be another more elegant (?) solution developing a plugin, but quickly modifying your code, in _includes/page_loop.html:
{% assign a = "something" %}
{% for i in a %}
{%if include.type == "name"%}
<li>{{ i.name }}</li>
{%else if include.type == "url"%}
<loc>{{ i.url }}</loc>
{%endif %}
{% endfor %}
Then each time you include page_loop.html pass an additional parameter specifying which type of output you want:
{% include page_loop.html type="name" %}
or
{% include page_loop.html type="url" %}

Twig set reusable piece of html

I'm creating some templates with Twig and have an issue.
I'm trying to load a piece of html that is used several times troughout a webshop. So my idea is to create a reusable piece of code that I can load everytime when needed.
The problem I'm facing is that when I do a for loop and then include that piece of code I get an empty return. With other words my code doesn't recognize the data that need to be loaded for each product in the for loop. It returns empty info boxes.
To clarify:
I have a main template index.html which calls a snippet to include some products (don't look at rain extension!!):
{% if featured %}
{% include 'snippets/products.rain' with {'products': featured, 'type': 'grid'} %}
{% endif %}
My products.rain snippet looks like this:
{% if type %}
{% if type == 'grid' %}
{% for product in products %} {# Products in this case = feautured products #}
<li class="item clearfix">.... etc etc .... </li>
{% endfor %}
{% elseif type == 'other-layout' %}
<div class="item">.... etc etc .... </div>
{% endif %}
{% endif %}
In the for loop there's html that's for 95% the same as in each for loop. I want to place that code inside a block that can be included in the for loops.
So what I did was:
{% set product_html %}
.... a lot of html ....
<a href="{{ product.url | url }}" title="{{ product.fulltitle }}">
<img src="{{ product.image }}" width="100" height="100" alt="{{ product.fulltitle }}"/>
</a>
{% endset %}
And then included in the for loop, like so:
{% if type %}
{% if type == 'grid' %}
{% for product in products %} {# Products in this case = feautured products #}
<li class="item clearfix">{{ product_html | raw }}</li>
{% endfor %}
{% elseif type == 'other-layout' %}
<div class="item">{{ product_html | raw }}</div>
{% endif %}
{% endif %}
However this returns the html that is set however with empty product.image and empty product.fulltitle.
I tried the same with set block, but that has the same result.
Is there anything I'm doing wrong....??
When you are using {% set %}, content inside your variable is not dynamic, it will only use data in your current context, see it live.
You can achieve your goal using 2 ways: using include or using macros.
As your piece of code for a product is small and not reused somewhere else, I suggest you to use macros:
{% macro product_html(product) %}
Current product is: {{ product }}
{% endmacro %}
{% import _self as macros %}
{% for product in products %}
{{ macros.product_html(product) }}
{% endfor %}
See it live

Jekyll 2.0 listing all post from category breaks

I moved from Jekyll pre-1.0 to 2.0 recently.
In my original code, on each blog post it will list all the title of posts that belongs to the same category as the current post being viewed. Previously this code worked:
{% for post in site.categories.[page.category] %}
<li {% if page.title == post.title %} class="active" {% endif %}>
{{ post.title }}</li>
{% endfor %}
However in the new version this does not work and I have to specify the category individually like so:
{% for post in site.categories.['NAME_OF_CATEGORY'] %}
Why can't I dynamically check for the category as before? And is there a work around for this instead of using if statements?
I figured it out. I had, in each post, my YAML front-matter category variables in uppercase or Camel case. Example: category: ABC or category: Zyx.
Doing page.category will always return the the actual category as it was written in the front-matter, which is ABC or Zyx. However site.categories.[CAT] only accepts CAT in lower cases (down case in liquid language).
Hence this will work site.categories.['abc'] or site.categories.['xyz'].
But this will fail site.categories.['ABC'] or site.categories.['Xyz']. It is the same as doing site.categories.[page.category].
Solution. Assign the current page category in lower case like so:
{% assign cat = page.category | downcase %}
{% for post in site.categories.[cat] %}
<li {% if page.title == post.title %} class="active" {% endif %}>
{{ post.title }}</li>
{% endfor %}

List tags within a specific category in Jekyll

I am migrating my Wordpress blog to Jekyll, which I like a lot so far. The current setup in the new site is like this:
use category to distinguish two types of posts (e.g., blog and portfolio)
use tag as normal
The challenge right now is to display all tags within a category because I want to create two separate tag clouds for two types of posts.
As far as I know, Liquid supports looping over all tags in a site like this:
{% for tag in site.tags %}
{{ tag | first }}
{% endfor %}
But I want to limit the scope to a specific category and am wishing to do something like this:
{% for tag in site['category'].tags %}
{{ tag | first }}
{% endfor %}
Any advice will be appreciated.
This seems to work for all kinds of filters like category or other front matter variables - like "type" so I can have type: article or type: video and this seems to get tags from just one of them if I put that in the 'where' part.
{% assign sorted_tags = site.tags | sort %}
{% for tag in sorted_tags %}
{% assign zz = tag[1] | where: "category", "Photoshop" | sort %}
{% if zz != empty %}
<li><span class="tag">{{ tag[0] }}</span>
<ul>
{% for p in zz %}
<li>{{ p.title }}</li>
{% endfor %}
</ul>
</li>
{% endif %}
{% endfor %}
zz is just something to use to filter above the first tag[0] since all it seems to have is the tag itself, so you can filter anything else with it. tag[1] has all of the other stuff.
Initially I was using if zz != null or if zz != "" but neither of them worked.
This will work, it will list only the tags on post of category 'X'. Replace X with the name of the category.
{% for post in site.categories['X'] %}
{% for tag in post.tags %}
{{ tag }}
{% endfor %}
{% endfor %}

Sorted navigation menu with Jekyll and Liquid

I'm constructing a static site (no blog) with Jekyll/Liquid. I want it to have an auto-generated navigation menu that lists all existing pages and highlight the current page. The items should be added to the menu in a particular order. Therefore, I define a weight property in the pages' YAML:
---
layout : default
title : Some title
weight : 5
---
The navigation menu is constructed as follows:
<ul>
{% for p in site.pages | sort:weight %}
<li>
<a {% if p.url == page.url %}class="active"{% endif %} href="{{ p.url }}">
{{ p.title }}
</a>
</li>
{% endfor %}
</ul>
This creates links to all existing pages, but they're unsorted, the sort filter seems to be ignored. Obviously, I'm doing something wrong, but I can't figure out what.
Since Jekyll 2.2.0 you can sort an array of objects by any object property. You can now do :
{% assign pages = site.pages | sort:"weight" %}
<ul>
{% for p in pages %}
<li>
<a {% if p.url == page.url %}class="active"{% endif %} href="{{ p.url }}">
{{ p.title }}
</a>
</li>
{% endfor %}
</ul>
And save a lot of build time compared to #kikito solution.
edit:
You MUST assign your sorting property as an integer weight: 10 and not as a string weight: "10".
Assigning sorting properties as string will ends up in a a string sort like "1, 10, 11, 2, 20, ..."
Your only option seems to be using a double loop.
<ul>
{% for weight in (1..10) %}
{% for p in site.pages %}
{% if p.weight == weight %}
<li>
<a {% if p.url == page.url %}class="active"{% endif %} href="{{ p.url }}">
{{ p.title }}
</a>
</li>
{% endif %}
{% endfor %}
{% endfor %}
</ul>
Ugly as it is, it should work. If you also have pages without a weight, you will have to include an additional internal loop just doing {% unless p.weight %} before/after the current internal one.
Below solution works on Github (doesn't require a plugin):
{% assign sorted_pages = site.pages | sort:"name" %}
{% for node in sorted_pages %}
<li>{{node.title}}</li>
{% endfor %}
Above snippet sorts pages by file name (name attribute on Page object is derived from file name). I renamed files to match my desired order: 00-index.md, 01-about.md – and presto! Pages are ordered.
One gotcha is that those number prefixes end up in the URLs, which looks awkward for most pages and is a real problem in with 00-index.html. Permalilnks to the rescue:
---
layout: default
title: News
permalink: "index.html"
---
P.S. I wanted to be clever and add custom attributes just for sorting. Unfortunately custom attributes are not accessible as methods on Page class and thus can't be used for sorting:
{% assign sorted_pages = site.pages | sort:"weight" %} #bummer
I've written a simple Jekyll plugin to solve this issue:
Copy sorted_for.rb from https://gist.github.com/3765912 to _plugins subdirectory of your Jekyll project:
module Jekyll
class SortedForTag < Liquid::For
def render(context)
sorted_collection = context[#collection_name].dup
sorted_collection.sort_by! { |i| i.to_liquid[#attributes['sort_by']] }
sorted_collection_name = "#{#collection_name}_sorted".sub('.', '_')
context[sorted_collection_name] = sorted_collection
#collection_name = sorted_collection_name
super
end
def end_tag
'endsorted_for'
end
end
end
Liquid::Template.register_tag('sorted_for', Jekyll::SortedForTag)
Use tag sorted_for instead of for with sort_by:property parameter to sort by given property. You can also add reversed just like the original for.
Don't forget to use different end tag endsorted_for.
In your case the usage look like this:
<ul>
{% sorted_for p in site.pages sort_by:weight %}
<li>
<a {% if p.url == page.url %}class="active"{% endif %} href="{{ p.url }}">
{{ p.title }}
</a>
</li>
{% endsorted_for %}
</ul>
The simplest solution would be to prefix the filename of your pages with an index like this:
00-home.html
01-services.html
02-page3.html
Pages are be ordered by filename. However, now you'll have ugly urls.
In your yaml front matter sections you can override the generated url by setting the permalink variable.
For instance:
---
layout: default
permalink: index.html
---
Easy solution:
Assign a sorted array of site.pages first then run a for loop on the array.
Your code will look like:
{% assign links = site.pages | sort: 'weight' %}
{% for p in links %}
<li>
<a {% if p.url == page.url %}class="active"{% endif %} href="{{ p.url }}">
{{ p.title }}
</a>
</li>
{% endfor %}
This works in my navbar _include which is simply:
<section id="navbar">
<nav>
{% assign tabs = site.pages | sort: 'weight' %}
{% for p in tabs %}
<span class="navitem">{{ p.title }}</span>
{% endfor %}
</nav>
</section>
I've solved this using a generator. The generator iterates over pages, getting the navigation data, sorting it and pushing it back to the site config. From there Liquid can retrieve the data and display it. It also takes care of hiding and showing items.
Consider this page fragment:
---
navigation:
title: Page name
weight: 100
show: true
---
content.
The navigation is rendered with this Liquid fragment:
{% for p in site.navigation %}
<li>
<a {% if p.url == page.url %}class="active"{% endif %} href="{{ p.url }}">{{ p.navigation.title }}</a>
</li>
{% endfor %}
Put the following code in a file in your _plugins folder:
module Jekyll
class SiteNavigation < Jekyll::Generator
safe true
priority :lowest
def generate(site)
# First remove all invisible items (default: nil = show in nav)
sorted = []
site.pages.each do |page|
sorted << page if page.data["navigation"]["show"] != false
end
# Then sort em according to weight
sorted = sorted.sort{ |a,b| a.data["navigation"]["weight"] <=> b.data["navigation"]["weight"] }
# Debug info.
puts "Sorted resulting navigation: (use site.config['sorted_navigation']) "
sorted.each do |p|
puts p.inspect
end
# Access this in Liquid using: site.navigation
site.config["navigation"] = sorted
end
end
end
I've spent quite a while figuring this out since I'm quite new to Jekyll and Ruby, so it would be great if anyone can improve on this.
I can get the code below works on with Jekyll/Liquid match to your requirement with category:
creates links to all existing pages,
sorted by weight (works as well on sorting per category),
highlight the current page.
On top of them it shows also number of post. All is done without any plug-in.
<ul class="topics">
{% capture tags %}
{% for tag in site.categories %}
{{ tag[0] }}
{% endfor %}
{% endcapture %}
{% assign sortedtags = tags | split:' ' | sort %}
{% for tag in sortedtags %}
<li class="topic-header"><b>{{ tag }} ({{ site.categories[tag] | size }} topics)</b>
<ul class='subnavlist'>
{% assign posts = site.categories[tag] | sort:"weight" %}
{% for post in posts %}
<li class='recipe {% if post.url == page.url %}active{% endif %}'>
{{ post.title }}
</li>
{% endfor %}
</ul>
</li>
{% endfor %}
</ul>
Check it on action on our networking page. You may click a post to highlight the navigation, as well a given link to bring you to the source page where their weight is assigned.
If you're trying to sort by weight and by tag and limit the number to 10, here's code to do it:
{% assign counter = '0' %}
{% assign pages = site.pages | sort: "weight" %}
{% for page in pages %}
{% for tag in page.tags %}
{% if tag == "Getting Started" and counter < '9' %}
{% capture counter %}{{ counter | plus:'1' }}{% endcapture %}
<li>{{page.title}}</li>
{% endif %}
{% endfor %}
{% endfor %}
The solution above by #kikito also worked for me. I just added a few lines to remove pages without weight from the navigation and to get rid of white space:
<nav>
<ul>
{% for weight in (1..5) %}
{% unless p.weight %}
{% for p in site.pages %}
{% if p.weight == weight %}
{% if p.url == page.url %}
<li>{{ p.title }}</li>
{% else %}
<li>{{ p.title }}</li>
{% endif %}
{% endif %}
{% endfor %}
{% endunless %}
{% endfor %}
</ul>
</nav>