Github Pages: adding an if condition in index.html - if-statement

Question

I have a blog created on Github Pages using Jekyll Now
The default Index.html looks like this
---
layout: default
---
<div class="posts">
{% for post in site.posts %}
<article class="post">
<h2>{{ post.title }}</h2>
<div class="entry">
{{ post.excerpt }}
</div>
Read More
</article>
{% endfor %}
</div>
This creates a landing page where the titles of all the posts you have made in the _posts directory are displayed with a link.
Looking at the {% for ... %} & {% endfor %} & the final static HTML, it seems as if when building the page, the for tag is actually iterated & the final HTML contains a list of actual titles.
I want to change this so that not all posts are listed. I do not want to list any post whose title contains the string "BEINGWRITTEN"
I tried stuff like
{% for post in site.posts %}
{% if (post.title.indexOf('BEINGWRITTEN') == -1) %}
<article class="post">
...
</article>
{% endif %}
{% endfor %}
Also tried with includes instead of indexOf, that also doesn't work. Both cases, I don't see any posts linked at all on the landing page.
How do I do this?

Answer 1

I did this by adding a category in the front matter of the page I don't want included.
i.e.
category: noshow
Then changed the index.html to
{% for post in site.posts %}
{% unless post.category == "noshow" %}
.....
{%endunless}
{%endfor}