通过管道符 "|" 来使用过滤器，{{ value|过滤器:参数 }}

Django 的模板语言中提供了六十个左右的内置过滤器

urls.py：

from django.conf.urls import url
from django.contrib import admin
from app01 import views

urlpatterns = [
    url(r'^filter_test/', views.filter_test),
]

 

如果一个变量的变量名不存在或者没有给其传值，可以通过 default 使用默认值

views.py：

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
        })

这里的 age 变量传了一个空值

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

</body>
</html>

name1 是没有定义的变量

运行效果：

Python - Django - 模板语言之 Filters（过滤器）

注意：

Python - Django - 模板语言之 Filters（过滤器）

这里不能带有空格

length：

返回字符串或列表的长度

views.py：

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    hobby = ["Reading", "Basketball", "Movie", "Music"]
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
            "hobby_list": hobby,
        })

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

<br>

<!-- length -->
{{ name|length }}
<br>
{{ hobby_list|length }}
<br>
{{ age|length }}

</body>
</html>

运行效果：

Python - Django - 模板语言之 Filters（过滤器）

这里计算了 name 变量值、hobby_list 列表、age 空值的长度

slice：

slice 是用来进行切片的

views.py：

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    hobby = ["Reading", "Basketball", "Movie", "Music"]
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
            "hobby_list": hobby,
        })

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

<br>

<!-- length -->
{{ name|length }}
<br>
{{ hobby_list|length }}
<br>
{{ age|length }}

<br>

<!-- 切片 -->
{{ hobby_list|slice:"0:2" }}
<br>
{{ name|slice:"0:2" }}

</body>
</html>

运行效果：

Python - Django - 模板语言之 Filters（过滤器）

filesizeformat：

将一串数字格式化成文件格式

views.py：

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    file_size = 988222836293733
    hobby = ["Reading", "Basketball", "Movie", "Music"]
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
            "hobby_list": hobby,
            "filesize": file_size,
        })

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

<br>

<!-- length -->
{{ name|length }}
<br>
{{ hobby_list|length }}
<br>
{{ age|length }}

<br>

<!-- 切片 -->
{{ hobby_list|slice:"0:2" }}
<br>
{{ name|slice:"0:2" }}

<br>

<!-- filesizeformat -->
{{ filesize|filesizeformat }}

</body>
</html>

运行结果：

Python - Django - 模板语言之 Filters（过滤器）

这里会根据大小格式化成 KB，MB，GB 和 TB

cut：

删除字符串或列表中和过滤器参数相同的内容

views.py：

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    file_size = 988222836293733
    hobby = ["Reading", "Basketball", "Movie", "Music"]
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
            "hobby_list": hobby,
            "filesize": file_size,
        })

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

<br>

<!-- length -->
{{ name|length }}
<br>
{{ hobby_list|length }}
<br>
{{ age|length }}

<br>

<!-- 切片 -->
{{ hobby_list|slice:"0:2" }}
<br>
{{ name|slice:"0:2" }}

<br>

<!-- filesizeformat -->
{{ filesize|filesizeformat }}

<br>

<!-- cut -->
{{ name|cut:"ac" }}
<br>
{{ hobby_list|cut:"Movie" }}

</body>
</html>

运行结果：

Python - Django - 模板语言之 Filters（过滤器）

Jack 被删除了 ac，hobby_list 列表被删除了 Movie

join：

连接字符串

views.py：

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    file_size = 988222836293733
    hobby = ["Reading", "Basketball", "Movie", "Music"]
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
            "hobby_list": hobby,
            "filesize": file_size,
        })

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

<br>

<!-- length -->
{{ name|length }}
<br>
{{ hobby_list|length }}
<br>
{{ age|length }}

<br>

<!-- 切片 -->
{{ hobby_list|slice:"0:2" }}
<br>
{{ name|slice:"0:2" }}

<br>

<!-- filesizeformat -->
{{ filesize|filesizeformat }}

<br>

<!-- cut -->
{{ name|cut:"ac" }}
<br>
{{ hobby_list|cut:"Movie" }}

<br>

<!-- join -->
{{ name|join:"+" }}
<br>
{{ hobby_list|join:"-" }}

</body>
</html>

运行结果：

Python - Django - 模板语言之 Filters（过滤器）

safe：

Django 模板会自动对 html、js 标签进行转义，safe 可以让 Django 不对标签进行转义

views.py：

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    file_size = 988222836293733
    test_html = "<a href='www.baidu.com'>这是一个 html 标签</a>"
    hobby = ["Reading", "Basketball", "Movie", "Music"]
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
            "hobby_list": hobby,
            "filesize": file_size,
            "test_html": test_html,
        })

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

<br>

<!-- length -->
{{ name|length }}
<br>
{{ hobby_list|length }}
<br>
{{ age|length }}

<br>

<!-- 切片 -->
{{ hobby_list|slice:"0:2" }}
<br>
{{ name|slice:"0:2" }}

<br>

<!-- filesizeformat -->
{{ filesize|filesizeformat }}

<br>

<!-- cut -->
{{ name|cut:"ac" }}
<br>
{{ hobby_list|cut:"Movie" }}

<br>

<!-- join -->
{{ name|join:"+" }}
<br>
{{ hobby_list|join:"-" }}

<br>

<!-- safe -->
{{ test_html }}
<br>
{{ test_html|safe }}

</body>
</html>

运行效果：

Python - Django - 模板语言之 Filters（过滤器）

没加 safe 的话就被 Django 默认转义了，加了 safe，a 标签就没被转义

truncatechars：

通过参数指定截断字符数，将多于指定的字符数的字符串字符进行截断，被截断的内容用 “...” 来代替

views.py:

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    file_size = 988222836293733
    test_html = "<a href='www.baidu.com'>这是一个 html 标签</a>"
    hobby = ["Reading", "Basketball", "Movie", "Music"]
    text = "abcdefghijklmnopqrstuvwxyz"
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
            "hobby_list": hobby,
            "filesize": file_size,
            "test_html": test_html,
            "text": text,
        })

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

<br>

<!-- length -->
{{ name|length }}
<br>
{{ hobby_list|length }}
<br>
{{ age|length }}

<br>

<!-- 切片 -->
{{ hobby_list|slice:"0:2" }}
<br>
{{ name|slice:"0:2" }}

<br>

<!-- filesizeformat -->
{{ filesize|filesizeformat }}

<br>

<!-- cut -->
{{ name|cut:"ac" }}
<br>
{{ hobby_list|cut:"Movie" }}

<br>

<!-- join -->
{{ name|join:"+" }}
<br>
{{ hobby_list|join:"-" }}

<br>

<!-- safe -->
{{ test_html }}
<br>
{{ test_html|safe }}

<br>

<!-- truncatechars -->
{{ text|truncatechars:10 }}

</body>
</html>

运行结果：

Python - Django - 模板语言之 Filters（过滤器）

date：

对时间进行格式化

views.py：

from django.shortcuts import render, redirect, HttpResponse
from app01 import models
import datetime


# Filter 测试
def filter_test(request):
    name = "Jack"
    age = 18
    file_size = 988222836293733
    test_html = "<a href='www.baidu.com'>这是一个 html 标签</a>"
    hobby = ["Reading", "Basketball", "Movie", "Music"]
    text = "abcdefghijklmnopqrstuvwxyz"
    now_time = datetime.datetime.now()
    return render(
        request,
        "filter_test.html",
        {
            "name": name,
            "age": None,
            "hobby_list": hobby,
            "filesize": file_size,
            "test_html": test_html,
            "text": text,
            "now_time": now_time,
        })

filter_test.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Filter 测试</title>
</head>
<body>

<h1>Filter 测试页面</h1>

<!-- default -->
{{ name }}
<br>
{{ name1|default:"这里不存在" }}
<br>
{{ age|default:"这里也不存在" }}

<br>

<!-- length -->
{{ name|length }}
<br>
{{ hobby_list|length }}
<br>
{{ age|length }}

<br>

<!-- 切片 -->
{{ hobby_list|slice:"0:2" }}
<br>
{{ name|slice:"0:2" }}

<br>

<!-- filesizeformat -->
{{ filesize|filesizeformat }}

<br>

<!-- cut -->
{{ name|cut:"ac" }}
<br>
{{ hobby_list|cut:"Movie" }}

<br>

<!-- join -->
{{ name|join:"+" }}
<br>
{{ hobby_list|join:"-" }}

<br>

<!-- safe -->
{{ test_html }}
<br>
{{ test_html|safe }}

<br>

<!-- truncatechars -->
{{ text|truncatechars:10 }}

<br>

<!-- 时间 -->
{{ now_time|date:"Y-m-d H:i:s"}}

</body>
</html>

运行结果：

Python - Django - 模板语言之 Filters（过滤器）