python：无法连接“str”和“long”对象
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python: cannot concatenate 'str' and 'long' objects
提问by Roger
I'm trying to set up a choice field in django, but I don't think this is a django issue. The choices field takes an iterable (e.g., a list or tuple) of 2-tuples to use as choices for this field.
我正在尝试在 django 中设置一个选择字段，但我认为这不是 django 问题。选择字段采用 2 元组的可迭代（例如，列表或元组）作为该字段的选择。
Here's my code:
这是我的代码：
self.fields['question_' + question.id] = forms.ChoiceField(
label=question.label,
help_text=question.description,
required=question.answer_set.required,
choices=[("fe", "a feat"), ("faaa", "sfwerwer")])
for some reason, i always get the following error:
出于某种原因，我总是收到以下错误：
TypeError - cannot concatenate 'str' and 'long' objects
The last line is always highlighted.
最后一行始终突出显示。
I'm not trying to concatenate anything. Almost regardless of what I change the list to for the 'choices' parameter, I get this error.
我不想连接任何东西。几乎无论我将“选择”参数的列表更改为什么，我都会收到此错误。
What's going on?
这是怎么回事？
采纳答案by Mark Rushakoff
Most likely it's highlighting the last line only because you split the statement over multiple lines.
很可能它突出显示最后一行只是因为您将语句拆分为多行。
The fix for the actualproblem will most likely be changing
实际问题的修复很可能会发生变化
self.fields['question_' + question.id]
to
到
self.fields['question_' + str(question.id)]
As you can quickly test in a Python interpreter, adding a string and a number together doesn't work:
由于您可以在 Python 解释器中快速测试，因此将字符串和数字相加是行不通的：
>>> 'hi' + 6
Traceback (most recent call last):
File "<pyshell#0>", line 1, in <module>
'hi' + 6
TypeError: cannot concatenate 'str' and 'int' objects
>>> 'hi' + str(6)
'hi6'
回答by kennytm
Probably question.idis an integer. Try
大概question.id是一个整数。尝试
self.fields['question_' + str(question.id)] = ...
instead.
反而。
回答by Sjoerd
'question_'is a string, question.idis a long. You can not concatenate two things of different types, you will have to convert the long to a string using str(question.id).
'question_'是一个字符串，question.id是一个长。你不能连接两个不同类型的东西，你必须使用str(question.id).
回答by Umang
self.fields['question_' + question.id]
That looks like the problem. Try
这看起来像问题。尝试
"question_%f"%question.id
or
或者
"question_"+ str(question.id)
回答by John La Rooy
This is a problem with doing too many things in one line - the error messages become slightly less helpful. Had you written it as below the problem would be much easier to find
这是在一行中做太多事情的问题 - 错误消息变得不太有用。如果你把它写成下面这个问题会更容易找到
question_id = 'question_' + question.id
self.fields[question_id] = forms.ChoiceField(
label=question.label,
help_text=question.description,
required=question.answer_set.required,
choices=[("fe", "a feat"), ("faaa", "sfwerwer")])
