How can I use break or continue within for loop in Twig template

Question

I try to use a simple loop  in my real code this loop is more complex  and I need to break this iteration like      for post in posts           if post id    10               break           endif         lt h2 gt    post heading    lt  h2 gt     endfor      How can I use behavior of break or continue of PHP control structures in Twig

User · Answer

I have found a good work-around for continue (love the break sample above). Here I do not want to list "agency". In PHP I'd "continue" but in twig, I came up with alternative:

{% for basename, perms in permsByBasenames %} 
    {% if basename == 'agency' %}
        {# do nothing #}
    {% else %}
        <a class="scrollLink" onclick='scrollToSpot("#{{ basename }}")'>{{ basename }}</a>
    {% endif %}
{% endfor %}

OR I simply skip it if it doesn't meet my criteria:

{% for tr in time_reports %}
    {% if not tr.isApproved %}
        .....
    {% endif %}
{% endfor %}

User · Answer

From  NHG comment      works perfectly     for post in posts slice 0 10

User · Answer

A way to be able to use    break    or    continue    is to write TokenParsers for them   I did it for the    break    token in the code below  You can  without much modifications  do the same thing for the    continue       AppBundle Twig AppExtension php   namespace AppBundle Twig   class AppExtension extends  Twig Extension       function getTokenParsers             return array              new BreakToken                          public function getName                 return  app extension            AppBundle Twig BreakToken php   namespace AppBundle Twig   class BreakToken extends  Twig TokenParser       public function parse  Twig Token  token                 stream    this- gt parser- gt getStream             stream- gt expect  Twig Token  BLOCK END TYPE               Trick to check if we are currently in a loop           currentForLoop   0           for   i   1  true   i                  try                      if we look before the beginning of the stream                    the stream will throw a  Twig Error Syntax                  token    stream- gt look - i                 catch   Twig Error Syntax  e                    break                             if   token- gt test  Twig Token  NAME TYPE   for                       currentForLoop                  else if   token- gt test  Twig Token  NAME TYPE   endfor                       currentForLoop--                                    if   currentForLoop  lt  1                throw new  Twig Error Syntax                   Break tag is only allowed in   for   loops                     stream- gt getCurrent  - gt getLine                     stream- gt getSourceContext  - gt getName                                     return new BreakNode               public function getTag                 return  break            AppBundle Twig BreakNode php   namespace AppBundle Twig   class BreakNode extends  Twig Node       public function compile  Twig Compiler  compiler                 compiler             - gt write  break  n                        Then you can simply use    break    to get out of loops like this      for post in posts           if post id    10               break           endif         lt h2 gt    post heading    lt  h2 gt     endfor        To go even further  you may write token parsers for    continue X    and    break X     where X is an integer    1  to get out continue multiple loops like in PHP

User · Answer

From docs TWIG docs       Unlike in PHP  it s not possible to break or continue in a loop    But still      You can however filter the sequence during iteration which allows you to skip items     Example 1  for huge lists you can filter posts using slice  slice start  length        for post in posts slice 0 10          lt h2 gt    post heading    lt  h2 gt     endfor      Example 2      for post in posts if post id  lt  10         lt h2 gt    post heading    lt  h2 gt     endfor      You can even use own TWIG filters for more complexed conditions  like      for post in posts onlySuperPosts         lt h2 gt    post heading    lt  h2 gt     endfor

User · Answer

This can be nearly done by setting a new variable as a flag to break iterating      set break   false       for post in posts if not break         lt h2 gt    post heading    lt  h2 gt         if post id    10               set break   true           endif       endfor      An uglier  but working example for continue      set continue   false       for post in posts           if post id    10               set continue   true           endif           if not continue             lt h2 gt    post heading    lt  h2 gt         endif           if continue               set continue   false           endif       endfor         But there is no performance profit  only similar behaviour to the built-in break and continue statements like in flat PHP

[php] How can I use break or continue within for loop in Twig template?

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