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Introduction: We covered the use of template variables in Django earlier. It’s easy to use, but what about template variables? The answer is yes, and that’s what this article is about — filters!

1. The filter

(1) Explanation of pure dry goods:

Function: Filter variables. Before rendering, the filter will process the variables according to the function, and then replace the original variables to display the results.
  • Grammar: {{fruits | lower}}

 

  • The pipe symbol makes a chain call (can be understood as nested use!) For example, implementing a feature that converts all characters to lowercase and the first character to uppercase.
  • Grammar: {{fruits | lower | capfirst}}

 

  • ** Use arguments: Filters can use arguments, followed by colons (), double quotes (), and arguments (). For example, to remove all whitespace from a string, use the cut filter.

Grammar: {{fruits | the cut: “”}} * *

  • Note:

When using arguments, there must be no space between the colon and the argument.

(2) Django filters:

The views.py file in the project directory:

from django.shortcuts import render
from django.http import HttpResponse

# Create your views here.

from datetime import datetime
def index(request) :
    test="THIS IS A LIST!"
    list= ["A"."B"."C"."D"."E"]
    data={
        'test':test,
        'xx':' '.'num1':1.'num2':2.'list':list.'now':datetime.now(),
        'html':'
hello django!!! 
'.'float':3.1415926
    }
    return render(request, "index.html", data)

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The index.html file in the templates folder of the project directory

<! DOCTYPE html> <html lang="en">
<head>
    <meta charset="UTF-8"> <title> Test! </title> </head> <body> {Unprocessed variables: #}
{{ test }}<br>

{# variables with a default value will use this value if Django considers it False. For example, an empty string,None. #}
{{ xx|default:'xxxxx' }}<br>

{# set the variable to use the default value only if it is None #}
{{ xx|default_if_none:'aaaaa'}}<br>

{Variable #}
{{ test|lower }}<br>

{Variable #}
{{ test|lower|capfirst }}<br>

{Add: string add, number add, list add, if failed, will return an empty string #}
{{ num1|add:num2 }}<br>

{Add two string variables #}
{{ test|add:xx }}<br>

{The first element of the list variable #}
{{ list|first }}<br>

{The last element of the list variable #}
{{ list|last }}<br>

{Default date-time format for data #}
{{ now|date }}<br>
{# default time format #}
{{ now|time }}<br>
{This is the 24-hour time format of the data filter #}
{{ now|date:'Y/m/d/H:i:s' }}<br>
{# this is the time filter in the 12-hour time format #}
{{ now|time:'h:i:s' }}<br>

{This is the same as joining in Python #}
{{ list|join:'oooo' }}<br>

{This is the string length method #}
{{ test|length }}<br>

{This is whether the length of the list is 4#}
{{ list|length_is:4 }}<br>

{* * * * * * * * * * * * * * * * *
{# this is a string that displays only 4 characters, leaving out the rest (but taking up 3 bits) #}
{{ test|truncatechars:7 }}<br>
{# this is a string that displays only 2 words, leaving out the rest (no placeholders) #}
{{ test|truncatewords:2 }}<br>

{This is a slice of string #}
{{ test|slice:'1:4' }}<br>

{This is a slice of the list #}
{{ list|slice:'2' }}<br>

{This is a string with an HTML tag #}
{{ html }}<br>

{This is to remove the HTML tag #} from the string.
{{ html|striptags }}<br>

{This is to turn off auto-escape and enable HTML tags in strings #}
{{ html|safe }}<br>

{# This is an unprocessed decimal #}
{{ float }}<br>
{This is a decimal number.
{{ float|floatformat }}<br>
{This is two decimal places.
{{ float|floatformat:'2' }}

</body>
</html>
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③ Effect display:

Date and time filter formats:

Extension – Introduction to automatic escape:

What is automatic escape?

Automatic escape is to escape some special characters of a variable, such as the left arrow (<) and right arrow (>), into HTML code in order to handle some unsafe variables.

< : escape into &lt; > < span style = "max-width: 100%; ': escape into &# 39;": escape into"; & : escape to &amp;Copy the code

🔆 In The End!

Start now, stick to it, a little progress a day, in the near future, you will thank you for your efforts!

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