Sometimes you want a specific piece of content to appear based on the content of a dynamic data. This is a very good use-case for an if:

{% if user.age < 18 %}
  <p>As a minor you need to obtain your parents approval.</p>
{% endif %}

If / Else

In some other occasion you might need to choose between two opposed options:

{% if client.type == "company" %}
  <p>{{client.companyName}} is represented by {{}}.</p>
{% else %}
  <p>{{}} represents herself only.</p>
{% endif %}

Other keywords

For more advanced cases you might be interested in the following keywords.

The unless keyword acts as the exact inverse of an if:

{% unless user.isBob %}
  <p>Your are not Bob!</p>
{% endunless %}

The if … elsif … else succession allows a bit more cases:

{% if client.isBob %}
  <p>You are Bob.</p>
{% elsif client.type == "person" %}
  <p>You are a person.</p>
{% else %}
  <p>You may be… a monkey.</p>
{% endif %}

When a dynamic data may contain several values and the content needs to change according to it, the case … when … else construct might be a good fit:

{% case client.type %}
  {% when "company" %}
    <p>Interested in our B2B offers?</p>
  {% when "person" %}
    <p>Interested in our B2C offers?</p>
  {% else %}
    <p>Interested in our offers?</p>
{% endcase %}