{% set numberList = [0,10,20,30,40,50,60,70,80,90] %}

{% for number in numberList %}
{% if loop.first %}
length {{ loop.length }} revindex {{ loop.revindex }}
{% endif %}
{{ loop.index }} => {{ number }}
{% endfor %}

{% for number in numberList if number < 50 %}
{% if loop.first %}
length {{ loop.length }} revindex {{ loop.revindex }}
{% endif %}
{{ loop.index }} => {{ number }}
{% endfor %}

{% for number in numberList if number < 10 %}
{% if loop.first %}
length {{ loop.length }} revindex {{ loop.revindex }}
{% endif %}
{{ loop.index }} => {{ number }}
{% endfor %}

length 10 revindex 10
1 => 0
2 => 10
3 => 20
4 => 30
5 => 40
6 => 50
7 => 60
8 => 70
9 => 80
10 => 90

length 4 revindex 4
1 => 0
2 => 10
3 => 20
4 => 30
5 => 40

length 1 revindex 1
1 => 0

length 10 revindex 10
1 => 0
2 => 10
3 => 20
4 => 30
5 => 40
6 => 50
7 => 60
8 => 70
9 => 80
10 => 90

length 5 revindex 5
1 => 0
2 => 10
3 => 20
4 => 30
5 => 40

length 2 revindex 2
1 => 0