django template实现定义临时变量,自定义赋值、自增实例

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

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)

 {% 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>

@register.filter
def div(value, div):
  '''
  分转化为元，保留两位小数
  :param value:
  :param div:
  :return:
  '''
  return round((value / div), 2)