Python jinja2 如何删除尾随换行符
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/36870953/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
jinja2 how to remove trailing newline
提问by Yunti
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
我正在使用 jinja 2 输出一个 yaml 文件，但似乎无法摆脱尾随换行符和 for 循环的结尾。例如下面
- 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:
给我输出：
- 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?
在 houseNo. 后面多了一个不需要的空行。我如何摆脱这条线？
回答by tknickman
Change your loop to strip white spaces from the top AND bottom of the output (notice extra "-" at the for loop close):
更改循环以从输出的顶部和底部去除空格（注意 for 循环关闭处的额外“-”）：
{% 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.
在我的测试中（使用https://github.com/abourguignon/jinja2-live-parser），“-”必须在第一个之后{%，而不是在最后一个之前，以实现您的要求。
Docs: http://jinja.pocoo.org/docs/dev/templates/#whitespace-control
文档：http: //jinja.pocoo.org/docs/dev/templates/#whitespace-control
回答by Scratch'N'Purr
I think you can get rid of it using the whitespace controlfeature. Thus I would modify the endforblock to {% endfor -%}
我认为您可以使用空白控制功能摆脱它。因此，我会将endfor块修改为{% endfor -%}
See if that does it!
看看行不行！
回答by MarredCheese
For those using Flask who arrive here, these lines did the trick for me:
对于那些使用 Flask 的人来说，这些行对我有用：
app = Flask(__name__)
app.jinja_env.lstrip_blocks = True
app.jinja_env.trim_blocks = True
回答by shuaiming
I found a way to solve this problem:
我找到了解决这个问题的方法：
- 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 }}
>,|: "clip": keep the line feed, remove the trailing blank lines.>-,|=: "strip": remove the line feed, remove the trailing blank lines.>+,|+: "keep": keep the line feed, keep trailing blank lines.
>,|: "clip": 保持换行，去掉尾随的空行。>-,|=: "strip": 去除换行符，去除尾随空行。>+,|+: "keep": 保持换行，保持尾随空行。
Thx Steve Bennett's post: In YAML, how do I break a string over multiple lines?
Thx Steve Bennett的帖子： 在 YAML 中，如何将一个字符串拆分成多行？
回答by spacether
You can suppress rendering of the below lines:
您可以禁止渲染以下几行：
<% for ... %>
<% endfor %>
<% if ... %>
<% endif %>
by setting trim_blocks=True and lstrip_blocks=True in your jinja2 environment. See the example below, info from their docs
通过在 jinja2 环境中设置 trim_blocks=True 和 lstrip_blocks=True 。请参阅下面的示例，来自他们文档的信息
context = {'querystring': querystring, 'path': path, 'content': content}
jinja_env = jinja2.Environment(loader=jinja2.FileSystemLoader('templates/'), trim_blocks=True, lstrip_blocks=True)
print(jinja_env.get_template('my_template.yaml').render(context))
