在django template中定义临时变量，并自定义操作：赋值、自增

定义临时变量：

{% with i=1 %}
{{i}}
{% endwith %}

定义对临时变量操作的tag

在templatetags中创建set_val.py

内容是

from django import template
import logging
register = template.Library()

class SetVarNode(template.Node):

def __init__(self, var_name, var_value):
self.var_name = var_name
self.var_value = var_value

def render(self, context):
try:
value = template.Variable(self.var_value).resolve(context)
except template.VariableDoesNotExist:
value = ""
context[self.var_name] = value
return u""

class VarAddOneNode(template.Node):

def __init__(self, var_name):
self.var_name = var_name

def render(self, context):
try:
value = template.Variable(self.var_name).resolve(context)
context[self.var_name] = str( int(value) + 1 )
except template.VariableDoesNotExist:
value = ""

return u""

def set_var(parser, token):
"""
{% set <var_name> = <var_value> %}
"""
parts = token.split_contents()
logging.info('len(parts)=' + str(len(parts)))
if len(parts) == 2:
content = parts[1]
if content[len(content)-2 :len(content)] == '++':
var_name = content[:len(content) - 2]
return VarAddOneNode(var_name)
else:
return u""
elif len(parts) == 4:
return SetVarNode(parts[1], parts[3])
# raise template.TemplateSyntaxError("'set' tag must be of the form: {% set <var_name> = <var_value> %}")

register.tag('set', set_var)然后在template中引入
{% load set_val %}

前端代码示例

{% load set_val %}
<div class="layui-form-item">
<div class="layui-form-label">商品尺码</div>
<div class="layui-input-block">
{% with i=1 %}

{% set i = 2 %}

{% for size in  size_list %}

<div class="layui-col-md2">
<div class="layui-row">
原名：{{ size.sizeName }}
</div>
名字：
<input style="width: 40px;display:inline;" type="text" name="color" ,
lay-verify="required"
autocomplete="off" placeholder=""
class="layui-input" value={{ size.sizeName }}>
<br>
<input type="checkbox" name="size{{ i }}" lay-skin="primary" checked="checked">
{% set i++ %}
</div>
{% endfor %}
{% endwith %}

</div>
</div>