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在Django中自定義filter并在template中的使用詳解

更新時間：2020年05月19日 10:58:27 作者：LiveMost

這篇文章主要介紹了在Django中自定義filter并在template中的使用詳解，具有很好的參考價值，希望對大家有所幫助。一起跟隨小編過來看看吧

Django內(nèi)置的filter有很多，然而我們由于業(yè)務(wù)邏輯的特殊要求，有時候仍然會不夠用，這個時候就需要我們自定義filter來實現(xiàn)相應(yīng)的內(nèi)容。接下來讓我們從自定義一個get_range(value)來產(chǎn)生列表的filter開始吧。

首先在你的django app的models.py的同級目錄建立一個templatetags的文件夾，并在里面新建一個init.py的空文件，這個文件確保了這個文件夾被當做一個python的包。在添加了templatetags模塊之后，我們需要重新啟動服務(wù)器才能使其有效。

polls/
  __init__.py
  models.py
  templatetags/
    __init__.py
  views.py

然后在templatetags中新建一個python文件，文件名就是以后需要加載到頁面的自定義庫的名字。在這里我們新建一個generalfilters.py文件。

polls/
  __init__.py
  models.py
  templatetags/
    __init__.py
    generalfilters.py
  views.py

為了讓庫生效，必須在文件里添加一個模塊級別的register變量。它是template.Library的實例，確保了標簽和過濾器的有效性。

編輯generalfilters.py，添加

from django import template
register=template.Library()
@register.filter
def get_range(value):
  return range(value)

上述代碼中定義了一個生成列表的函數(shù)，@register.filter表示這個函數(shù)是一個過濾器。至此我們的生成列表的過濾器就已經(jīng)寫好了。接下來我們需要把這個過濾器的庫加載到模板里。

在你想要使用的模板的頂部加上{% load generalfilters %}，就可以使用這個過濾器了。

{% for i in 5|get_range_bet_within %}
  {{i}}
{% endfor %}

運行結(jié)果

補充知識：Django 自定義篩選器：重寫DateFieldListFilter

我就廢話不多說了，大家還是直接看代碼吧！

class MyDateTimeFilter(admin.filters.DateFieldListFilter):
  def __init__(self, *args, **kwargs):
    super(MyDateTimeFilter, self).__init__(*args, **kwargs)
 
    now = timezone.now()
    # When time zone support is enabled, convert "now" to the user's time
    # zone so Django's definition of "Today" matches what the user expects.
    if timezone.is_aware(now):
      now = timezone.localtime(now)
 
    filter_end_date = now.replace(hour=0, minute=0, second=0, microsecond=0)
 
    filter_start_date_for_one_week = filter_end_date - datetime.timedelta(days=7)
 
    month_with_day31 = [1,3,5,7,8,10,12]
    if filter_end_date.month in month_with_day31 and filter_end_date.day == 31 and filter_end_date.month != 3:
      if filter_end_date.month == 1:
        filter_start_date_for_one_month = filter_end_date.replace(year=filter_end_date.year-1, month=12)
      else:
        filter_start_date_for_one_month = filter_end_date.replace(month=filter_end_date.month-1, day=30)
    elif filter_end_date.month == 3 and filter_end_date.day in [29, 30, 31]:
      if is_leap_year(filter_end_date.year):
        filter_start_date_for_one_month = filter_end_date.replace(month=filter_end_date.month-1, day=29)
      else:
        filter_start_date_for_one_month = filter_end_date.replace(month=filter_end_date.month-1, day=28)
    else:
      if filter_end_date.month == 1:
        filter_start_date_for_one_month = filter_end_date.replace(year=filter_end_date.year-1, month=12)
      else:
        filter_start_date_for_one_month = filter_end_date.replace(month=filter_end_date.month-1)
    
    filter_start_date_for_six_month = ''
    filter_start_date_for_six_month_month = (filter_end_date.month - 6 + 12) % 12
    if filter_start_date_for_six_month_month == 0:
      filter_start_date_for_six_month_month = 12
    if filter_start_date_for_six_month_month in month_with_day31:
      if filter_end_date.month > 6:
        filter_start_date_for_six_month = filter_end_date.replace(month=filter_start_date_for_six_month_month)
      else:
        filter_start_date_for_six_month = filter_end_date.replace(year=filter_end_date.year-1, month=filter_start_date_for_six_month_month)
    elif filter_start_date_for_six_month_month == 2:
      if filter_end_date.day in [29, 30, 31]:
        if is_leap_year(filter_end_date.year):
          filter_start_date_for_six_month = filter_end_date.replace(month=filter_start_date_for_six_month_month, day=29)
        else:
          filter_start_date_for_six_month = filter_end_date.replace(month=filter_start_date_for_six_month_month, day=28)
      else:
        filter_start_date_for_six_month = filter_end_date.replace(month=filter_start_date_for_six_month_month)
    else:
      if filter_end_date.day == 31 and filter_end_date.month >6:
        filter_start_date_for_six_month = filter_end_date.replace(month=filter_start_date_for_six_month_month, day=30)
      elif filter_end_date.day == 31 and filter_end_date.month <=6:
        filter_start_date_for_six_month = filter_end_date.replace(year=filter_end_date.year-1, month=filter_start_date_for_six_month_month, day=30)
      elif filter_end_date.day <31 and filter_end_date.month >6:
        filter_start_date_for_six_month = filter_end_date.replace(month=filter_start_date_for_six_month_month)
      else:
        filter_start_date_for_six_month = filter_end_date.replace(year=filter_end_date.year-1, month=filter_start_date_for_six_month_month)
 
    filter_end_date = filter_end_date + datetime.timedelta(days=1)
 
    self.links = ((
      ('------', {}),
      ('Past week', {
        self.lookup_kwarg_since: str(filter_start_date_for_one_week),
        self.lookup_kwarg_until: str(filter_end_date),
      }),
      ('Past month', {
        self.lookup_kwarg_since: str(filter_start_date_for_one_month),
        self.lookup_kwarg_until: str(filter_end_date),
      }),
      ('Past 6 months', {
        self.lookup_kwarg_since: str(filter_start_date_for_six_month),
        self.lookup_kwarg_until: str(filter_end_date),
      }),
      ('All', {}),
    ))

以上這篇在Django中自定義filter并在template中的使用詳解就是小編分享給大家的全部內(nèi)容了，希望能給大家一個參考，也希望大家多多支持腳本之家。

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