字符串索引超出Python，Django [英] string index out of range Python, Django

问题描述

我正在使用Django开发Web应用程序。当我尝试在我的网络表单上运行它，我收到'字符串索引超出范围'错误。但是，当我将一本字典硬编码到一个python测试文件中时，它工作正常，具有相同的值。

这是我的Django视图：

  def submitworkout（request） ：
 #workoutinfo = workout（request.GET）
 return render_to_response（'home.html'，{'infoprompt'：workout（request.GET）}，context_instance = RequestContext（request））
  

这是对象：

 code> class workout（）：
 
 
 def __init __（self，addworkout）：
 self.workout = collections.OrderedDict（）; 
 getallreps = 0 
对于我的范围（len（addworkout ['exercisename']））：
 numsetcounter = 0; 
 self.workout [string.capwords（addworkout ['exercisename'] [i]）] = [] 
 while numsetcounter< int（addworkout ['numsets'] [i]）：
＃print self.workout [addworkout ['exercisename'] [i]] 
 self.workout [string.capwords（addworkout ['exercisename' ] [i]）]。append（[addworkout ['weightinputboxes]] [getallreps]，addworkout ['repinputboxes'] [getallreps]] 
＃[
 getallreps + = 1 
 numsetcounter + = 1 
 
 def getexercise（self，name）：
 try：
 return self.workout [string.capwords（name）]; 
除了：
返回'此练习不存在！'
  

现在这个是我正在尝试通过课程的字典：

  addworkout = 
 {u'repinputboxes'：[ u'5'，u'3']，u'weightinputboxes'：[u'195'，u'170']，u'numsets'：[u'1'，u'1']，u'exercisename' [u'Squat'，u'Power Clean']} 
  

这里是Django的本地vars显示错误：

  i = 1 
 
 numsetcounter = 0 
 
 getallreps = 1 
  

希望你们帮我解决问题。提前致谢！

编辑：追溯

 环境：
 
 
请求方法：GET 
请求URL：http：// localhost：8000 / submitworkout /？exercisename = Squat& numsets = 1& weightinputboxes = 195& repinputboxes = 5& exerciseisename = Power + Clean& numsets = 1& weightinputboxes = 170& repinputboxes = 3 
 
 Django版本：1.3.1 
 Python版本：2.7.0 
安装的应用程序：
（'django。 contrib.auth'，
'django.contrib.contenttypes'，
'django.contrib.sessions'，
'django.contrib.sites'，
'django.contrib。消息'，
'django.contrib.staticfiles'，
'django.contrib.admin'，
'authentication'）
安装的中间件：
（'django。 middleware.common.CommonMiddleware'，
'django.contrib.sessions.middleware.SessionMiddleware'，
'django.middleware.csrf.CsrfViewMiddleware'，
'django.contrib.auth.middleware。 AuthenticationMiddleware'，
'django.contri b.messages.middleware.MessageMiddleware'）
 
 
追溯：
文件C：\Python27\lib\site-packages\django\core\ get_response 
 111. response = callback（request，* callback_args，** callback_kwargs）
文件C：\Users\Chris\testdjango\fitness\ submit.py
 34. return render_to_response（'home.html'，{'infoprompt'：workout（request.GET）}，context_instance = RequestContext（request））
文件C：\\ _Usin\Chris\testdjango\fitness\tracking\models.py__init__ 
 15.而numsetcounter < int（addworkout ['numsets'] [i]）：＃u'numsets'：[u'1'，u'2'] 
 
异常类型：IndexError at / submitworkout / 
异常值：字符串索引超出范围
  

解决方案

问题是您正在使用 QueryDict 对象 request.GET中。 QueryDict从请求的查询字符串初始化。在GET请求中传递值列表的方式就像 baz = 1& baz = 2 。当您直接通过密钥访问该值时，就像它是一个普通的dict，你只会得到最后添加的值。

使用QueryDict正确使用<一个href =https://docs.djangoproject.com/en/dev/ref/request-response/#django.http.QueryDict.getlist =nofollow> getlist ：

  exercise = addworkout.getlist（'exercisename'）
 numsets = addworkout.getlist（'numsets'）
  

这将正确返回值列表。

另一个选项是简单将QueryDict转换为正常的dict，然后将其传递给您的其他方法。这样，它将具有所有正常的扩展值：

  workout（dict（request.GET））
  

这实际上是一个很好的主意，因为您的锻炼方法不必具有QueryDict对象的特殊知识。它可以像一个正常的命令一样对待它。除了特定的视图相关情况，它可以被任何类似字典的数据结构所使用。

i'm using Django to develop a web application. When i try and run it on my web form i am receiving 'string index out of range' error. However, when i hardcode a dictionary in to a python test file it works fine with the same values.

Here is my Django View:

def submitworkout(request):
    #workoutinfo = workout(request.GET)
    return render_to_response('home.html',{'infoprompt': workout(request.GET)},context_instance=RequestContext(request))

Here is the object:

class workout():


    def __init__(self,addworkout):
        self.workout = collections.OrderedDict();
        getallreps = 0
        for i in range(len(addworkout['exercisename'])): 
            numsetcounter = 0; 
            self.workout[string.capwords(addworkout['exercisename'][i])] = [] 
            while numsetcounter < int(addworkout['numsets'][i]):   
                # print self.workout[addworkout['exercisename'][i]]
                self.workout[string.capwords(addworkout['exercisename'][i])].append([addworkout['weightinputboxes'][getallreps],addworkout['repinputboxes'][getallreps]]) 
                #[
                getallreps +=1
                numsetcounter +=1  

    def getexercise(self,name): 
        try: 
            return self.workout[string.capwords(name)];
        except:
            return 'This exercise does not exist!'

Now this is the dictionary i'm trying to run through the class:

addworkout =    
 {u'repinputboxes': [u'5', u'3'], u'weightinputboxes': [u'195', u'170'], u'numsets': [u'1', u'1'], u'exercisename': [u'Squat', u'Power Clean']}

and here are the local vars that Django is displaying on the error:

i=1 

numsetcounter =0

getallreps = 1

Hopefull you guys help me resolve my problem. Thanks in advance!

EDIT: Traceback

Environment:


Request Method: GET
Request URL: http://localhost:8000/submitworkout/?exercisename=Squat&numsets=1&weightinputboxes=195&repinputboxes=5&exercisename=Power+Clean&numsets=1&weightinputboxes=170&repinputboxes=3

Django Version: 1.3.1
Python Version: 2.7.0
Installed Applications:
('django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.admin',
 'authentication')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware')


Traceback:
File "C:\Python27\lib\site-packages\django\core\handlers\base.py" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File "C:\Users\Chris\testdjango\fitness\views.py" in submitworkout
  34.     return render_to_response('home.html',{'infoprompt': workout(request.GET)},context_instance=RequestContext(request))
File "C:\Users\Chris\testdjango\fitness\tracking\models.py" in __init__
  15.             while numsetcounter < int(addworkout['numsets'][i]):   # u'numsets': [u'1', u'2']

Exception Type: IndexError at /submitworkout/
Exception Value: string index out of range

解决方案

The problem is in the way you are using the QueryDict object from request.GET. A QueryDict is initialized from the request's query string. The way a list of values are passed in a GET request is like baz=1&baz=2. When you directly access the value by a key as if it were a normal dict, you are only ever getting the last value that was added.

Use the QueryDict properly using getlist:

exercises = addworkout.getlist('exercisename')
numsets = addworkout.getlist('numsets')

This will properly return lists of values.

Another option is to simply convert the QueryDict to a normal dict before passing it into your other method. This way it will have all the normal expanded values:

workout(dict(request.GET))

This is actually a really good idea because then your workout method won't have to have special knowledge of the QueryDict object. It can just treat it like a normal dict. It can then be used by any dictionary-like data structure besides a specific view-related situation.

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