Python 类型错误：float() 参数必须是 Django 距离中的字符串或数字
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TypeError: float() argument must be a string or a number in Django distance
提问by Sachi Tekina
I tried to get the value from my template which is kmdistancebut it returns an error when I view the page.
我试图从我的模板中获取值，kmdistance但是当我查看页面时它返回一个错误。
Here's the views.py
这是views.py
def display_maps(request):
#bases for city proper
pnt = ButuanMaps.objects.get(clandpin='162-03-0001-017-33').geom
#landproperty__sownerid__id=5 is for government user
kmdistance = request.GET.get("kmtocity", None)
mysection = (request.GET.get("mysection", None))
query_section = Section.objects.all().order_by('id')
...
query_maps = ButuanMaps.objects.filter(landproperty__sownerid__id=5, geom__distance_lte=(pnt, D(km=kmdistance)), ssectionid__id=mysection)
...
Here's the template.html
这是模板.html
<select name="kmtocity" class="form-control">
<option type="text" value="empty">Select Km. away from City Proper</option>
<option value="1">1</option>
<option value="5">5</option>
<option value="10">10</option>
<option value="15">15</option>
<option value="20">20</option>
</select>
It works fine when I tried putting the value in distance.
当我尝试将值放在距离上时，它工作正常。
采纳答案by u1860929
You are defaulting to a None value when the kmdistanceis not found in the request.GETdirectory here
如果kmdistance在request.GET此处的目录中找不到，则默认为 None 值
kmdistance = request.GET.get("kmtocity", None)
kmdistance = request.GET.get("kmtocity", None)
As such, when you convert None to a float later, it throws up an error
因此，当您稍后将 None 转换为浮点数时，它会引发错误
TypeError: float() argument must be a string or a number
To overcome this, wherever you are converting to float, just check that the kmdistance value exists, and then convert it to float
为了克服这个问题，无论您在哪里转换为浮点数，只需检查 kmdistance 值是否存在，然后将其转换为浮点数
if kmdistance is not None:
kmdistance = float(kmdistance)
Alternatively, use a different default value, like 0 instead of None(though 0 kmdistance may imply wrong value for km distance, so you can use another default value like 100 which works for you)
或者，使用不同的默认值，例如 0 而不是None（尽管 0 kmdistance 可能意味着 km 距离的值是错误的，因此您可以使用另一个适合您的默认值，例如 100）
