树枝中的逗号分隔列表

Question

What is the shortest (and clearest) way to add comma after each element of the list except the last one?

{% for role in user.roles %}
    {{ role.name }},
{% endfor %}

This example will add comma after all lines, including the last one.

Answer 1

Don't know about shortest but this could be clear. Try the following to add comma after all lines in the loop except the last one:

{% for role in user.roles %}
    {{ role.name }}
    {% if not loop.last %},{% endif %}
{% endfor %}

Shorter version as suggested in comments:

{% for role in user.roles %}
    {{ role.name }}
    {{ not loop.last ? ',' }}
{% endfor %}

Answer 2

这适用于 Symfony 2.3.x 但应该适用于每个 2.x 版本：

{{ user.roles|join(', ') }}

Answer 3

{{- not loop.last ? ',' : '' -}}

Answer 4

{{ user.roles|column('title')|join(', ') }}

Answer 5

Since the OP asked for iterating on name key of a role .

Shortest would be:

{{ user.roles|column('name')|join(', ') }}

where user.roles is a list of user roles.

Answer 6

Here is how I managed to print author names (in authors array) in some scientific publication format using twig's local loop variable in for loop-

    {% spaceless %}
     {% for author in authors %}
      {{- loop.last ? ' and ' : (not loop.first ? ', ') -}}
      {{- author -}}
     {% endfor %}
    {% endspaceless %}

The output is something like

• For 1 author

  Author1

• For 2 authors

  Author1 and Author2

• For 3 or more authors

  Author1, Author2, and Author3