Remove trailing comma from an output loop?

Question

I want to create a comma separated list of categories to which an entry belongs, but without the trailing slash on the last element... can't work out how to remove it!

{% for category in entry.mediaType %}
    <b>{{ category.title }}</b>,
{% endfor %}

Answer 1

There is a special tag inside for loops you can use for this

{% for category in entry.mediaType %}
    <b>{{ category.title }}</b>,
    {% if loop.last %}
        <b>{{ category.title }}</b>
    {% endif %}
{% endfor %}

Full list here

Answer 2

While your conditional is complete personally preference I would do the following as I find it slightly easier to read. Note the use of the {%- if -%} to trim whitespace:

{% for category in entry.mediaType %}
    <b>{{ category.title }}</b>
    {%- if not loop.last -%}
      ,
    {% endif %}
{% endfor %}

Answer 3

{% for category in entry.mediaType %}
    <b>{{ category.title }}</b>{{ "," if not loop.last }}
{% endfor %}