jinja2 how to remove trailing newline

Question

I'm using jinja 2 to output a yaml file but can't seem to get rid of a trailing newline and the end of a for loop. Eg the below

 - request:
        path: {{ path }}
        headers:
          origin: 'somedomain.com'
          user-agent: 'agent'
          referer: 'some.domain.com'
          authority: 'somedomain.com'
        querystring:
          {% for key, value in querystring.items() -%}
          {{ key }}: '{{ value }}'
          {% endfor %}
      response:
        content:
          file: {{ content }}

gives me the output:

- request:
    path: /some/path
    headers:
      origin: 'somedomain.com'
      user-agent: 'agent'
      referer: 'somedomain.com'
      authority: 'somedomain.com'
    querystring:
      postcode: 'xxxxxx'
      houseNo: '55'

  response:
    content:
      file: address.json

With an additional unwanted blank line after houseNo. How do I get rid of this line?

Answer 1

Change your loop to strip white spaces from the top AND bottom of the output (notice extra "-" at the for loop close):

 {% for key, value in querystring.items() -%}
      {{ key }}: '{{ value }}'
 {%- endfor %}

In my tests (using https://github.com/abourguignon/jinja2-live-parser), the "-" must come after the first {%, not before the last to achieve what you're asking for.

Docs: http://jinja.pocoo.org/docs/dev/templates/#whitespace-control