How to use group_by filter with the first element of an array?
I use this like:
{% assign categories = Object | group_by:"categories[0]" %}
Is there a way in Jinja2 to construct a variable name and then call it? I want to do something like this:
{% for type in ('Students', 'Faculty', 'Groups') %}
{% set import_name = 'latest_' + type|lower + '_import' %}
{{ type }}: {{ import_name.created_at }}
{% endfor %}
I would expect the output to be something like this:
Students: 5/26/2016
Faculty: 5/25/2016
Groups: 5/25/2016
I have the variables latest_students_import, latest_faculty_import, and latest_groups_import set in the template scope, and would like to avoid having a large conditional in my for loop. I set import_name based on the type, and then try to "call" import_name. I want something like {{ call(import_name) }}. Is this possible, or is there another way I can go about this?
In this case, I suppose I could do it in reverse order loop through the three template variable names, and then "print" the shortened name, capitalized, but I would prefer to do it this way.
One possibility is to create a dict or a list on the server-side which contains your variables. You can then send that object to Jinja as a template variable. As it stands you are just setting import_name equal to string, which won't have the .created_at attribute.
I use liquid syntax with Jekyll. I use
{% assign projects = (site.pages | where: "categories" , "project") %}
For filter the pages with that categories. How can I add another criteria as "and" or "or"???
Ok,
I find the solution...very easy. Simple I put
site.categories['project'] | where: 'featured',true
and it filter with and and type
I'm using Google app engine and I'm trying to set the value of a textarea based on the concatenation of two string variables. Let's say I have 4 items, and each item has multiple fields. So in my Python I'm passing the dictionary { 'value0': newValue }. I'm using a for loop (iterator value num) and I want to use in my HTML something equivalent to {{ value }}{{ num }} where the variable referenced is value0.
I've tried {{ value~num }} but nothing works. If I could use an array that would be even better - such as {{ value[num] }}
I'm trying to pick a random element from an array -- is this possible using Liquid/Jekyll?
I can create an array -- and access a given index ... but is there a way to "shuffle" the array and then select an index, and thus get a random element from the array?
prefix: ["Foo", "Bar", "Baz"]
---
{{ page.prefix[1] }}
# outputs "Bar"
The 2018 answer is
{% assign prefix = page.prefix | sample: 2 %}
{{ prefix[0] }}
As the OP asked about Jekyll, this can be found at: https://jekyllrb.com/docs/templates/
Liquid doesn't have a filter for picking a random element from an array or an integer interval.
If you want Jekyll to do that, you would have to create an extension to add that liquid filter.
However, I must point out that doing so would pick a random element every time the page is generated, but not every time the page is viewed.
If you want to get different random values every time you visit a page, your best option is using javascript and letting the client pick a random value. You can use liquid to generate the relevant javascript though.
You may be able to do that just in Liquid, but it could less of generic solution like the one provided by #Brendan. According to this article, you can generate a random liquid number between min & max. So simply:
Assign the min to 0 and max to your array's length.
Loop over the array till you find your random number and pick you element.
Here is an example, get your random array index:
{% assign min = 0 %}
{% assign max = prefix.size %}
{% assign diff = max | minus: min %}
{% assign randomNumber = "now" | date: "%N" | modulo: diff | plus: min %}
Then find your random value:
{{ prefix[randomNumber] }}
You can create a plugin to get a random element. Something like this:
module Jekyll
module RandomFilter
# Use sample to get a random value from an array
#
# input - The Array to sample.
#
# Examples
#
# random([1, 2, 3, 4, 5])
# # => ([2])
#
# Returns a randomly-selected item out of an array.
def random(input)
input.sample(1)
end
end
end
Liquid::Template.register_filter(Jekyll::RandomFilter)
Then do something like this in your template to implement:
{% assign myArray = '1|2|3|4|5 | split: '|' %}
{% assign myNumber = myArray | random %}
Without using a plugin (which might be a requirement if you are using github pages for example) and don't want the choice to be set only at build/rebuild time.
This uses collections as it's data source and some feature flags set in the page front matter.
{% if page.announcements %}
<script>
// homepage callout
var taglines=[
{% for txt in site.announcements %}
{{ txt.content | markdownify | jsonify | append: "," }}
{% endfor %}
]
var selection = document.querySelector('#tagline') !== null;
if(selection) {
document.querySelector('#tagline').innerHTML = taglines[ Math.floor(Math.random()*taglines.length) ];
}
</script>
{% endif %}
I use markdownify to process the content, jsonify to make it JavaScript safe and then append a comma to make my array.
The Javascript then populates one randomly at page load.
Add collection to config.yml
collections:
announcements:
Add flag to page
---
layout: home
title:
slider: true
announcements: true
---
collection content item (test.md)
---
published: true
---
This is a test post
You could adapt Liquid::Drop and whitelist Ruby's sample method.
See https://github.com/Shopify/liquid/blob/master/lib/liquid/drop.rb#L69:
You would need to change:
blacklist -= [:sort, :count, :first, :min, :max, :include?]
to:
blacklist -= [:sort, :count, :first, :min, :max, :include?, :sample]
Next you could just use:
{{ some_liquid_array.sample }}