如何在 django 模板中向自定义模板筛选器添加多个参数?

这是我定制的过滤器:

from django import template


register = template.Library()


@register.filter
def replace(value, cherche, remplacement):
return value.replace(cherche, remplacement)

下面是我在模板文件中尝试使用它的方法,结果导致了一个错误:

{{ attr.name|replace:"_"," " }}
{{ attr.name|replace:"_" " " }}
{{ attr.name|replace:"_":" " }}
{{ attr.name|replace:"cherche='_', remplacement=' '" }}

我研究了 姜戈的文件,但只找到了使用单个参数的例子... ... 这可能吗?

105574 次浏览

This feature has been marked as WONTFIX in 2013 Django's Trac: http://code.djangoproject.com/ticket/1199

Not possible according to this section of the docs:

Custom filters are just Python functions that take one or two arguments:

  • The value of the variable (input) -- not necessarily a string.
  • The value of the argument -- this can have a default value, or be left out altogether.

It is possible and fairly simple.

Django only allows one argument to your filter, but there's no reason you can't put all your arguments into a single string using a comma to separate them.

So for example, if you want a filter that checks if variable X is in the list [1,2,3,4] you will want a template filter that looks like this:

{% if X|is_in:"1,2,3,4" %}

Now we can create your templatetag like this:

from django.template import Library


register = Library()


def is_in(var, args):
if args is None:
return False
arg_list = [arg.strip() for arg in args.split(',')]
return var in arg_list


register.filter(is_in)

The line that creates arg_list is a generator expression that splits the args string on all the commas and calls .strip() to remove any leading and trailing spaces.

If, for example, the 3rd argument is an int then just do:

arg_list[2] = int(arg_list[2])

Or if all of them are ints do:

arg_list = [int(arg) for arg in args.split(',')]

EDIT: now to specifically answer your question by using key,value pairs as parameters, you can use the same class Django uses to parse query strings out of URL's, which then also has the benefit of handling character encoding properly according to your settings.py.

So, as with query strings, each parameter is separated by '&':

\{\{ attr.name|replace:"cherche=_&remplacement= " }}

Then your replace function will now look like this:

from django import template
from django.http import QueryDict


register = template.Library()


@register.filter
def replace(value, args):
qs = QueryDict(args)
if qs.has_key('cherche') and qs.has_key('remplacement'):
return value.replace(qs['cherche'], qs['remplacement'])
else:
return value

You could speed this up some at the risk of doing some incorrect replacements:

qs = QueryDict(args)
return value.replace(qs.get('cherche',''), qs.get('remplacement',''))

Heres a bad idea but works:

\{\{ xml|input_by_xpath:"{'type':'radio','xpath':'//result/value'}" }}

and

@register.filter
def input_by_xpath(device, args):
args = eval(args)
...
result = "<input type=\"%s\" value=\"%s\" name=\"%s\"/>"%(args['type'],value,args['xpath'])
return mark_safe(result)

<my-site>/globaltags/replace.py

from django.template import Library


import re


register = Library()


def search(value, search):
return re.sub(search, '#f4x@SgXXmS', value)


def replace(value, replace):
return re.sub('#f4x@SgXXmS', replace, value)


register.filter(search)
register.filter(replace)

In the template:

\{\{ "saniel"|search:"s"|replace:"d" }}

Instead of a filter, register your tag as a simple tag. Those can take multiple arguments. The syntax for invoking it will be a little bit different, but that's just syntactic sugar changing.

It's easy like this.

@register.filter(name='one_more')
def one_more(_1, _2):
return _1, _2


def your_filter(_1_2, _3)
_1, _2 = _1_2
print "now you have three arguments, enjoy"


\{\{ _1|one_more:_2|your_filter:_3 }}

You can just simply do this:

{% assign find_total_issued = dailysalesreport | find: "TotalIssued":"13" %}


public static List<object> Find(object collection, string column, string value)

And it will reach the destination as the abstraction of the function is sjare.

It is more simple than you think

You can use simple_tag for this.

from django import template
register = template.Library()


@register.simple_tag
def multiple_args_tag(a, b, c, d):
#do your stuff
return

In Template:

{% multiple_args_tag 'arg1' 'arg2' 'arg3' 'arg4' %}

NOTE: Don't forget to re-run the server.