禁止“无"在Jinja2中输出为字符串 [英] Suppress "None" output as string in Jinja2

问题描述

当值None时，如何说服Jinja2不打印"None"?

How do I persuade Jinja2 to not print "None" when the value is None?

我在词典中有很多条目，我想在一个循环中输出所有内容，而不是针对不同的关键字使用特殊情况.如果我的值是None(NoneType不是字符串)，则将字符串"None"插入模板渲染结果中.

I have a number of entries in a dictionary and I would like to output everything in a single loop instead of having special cases for different keywords. If I have a value of None (the NoneType not the string) then the string "None" is inserted into the template rendering results.

尝试使用抑制它 {{ value or '' }}效果很好，因为它也会替换数字零.

Trying to suppress it using {{ value or '' }} works too well as it will replace the numeric value zero as well.

在将字典传递给Jinja2进行渲染之前，我是否需要过滤字典?

Do I need to filter the dictionary before passing it to Jinja2 for rendering?

推荐答案

在Jinja2(2.9+)的新版本中:

In new versions of Jinja2 (2.9+):

{{ value if value }}

在Jinja2的较早版本(2.9之前)中:

In older versions of Jinja2 (prior to 2.9):

{{ value if value is not none }}效果很好.

如果这引起了关于没有其他的错误，请尝试使用else ..

if this raises an error about not having an else try using an else ..

{{ value if value is not none else '' }}

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