的Python：類型錯誤：「NoneType」對象沒有屬性「__getitem__」

Question

當我通過終端米運行我Python代碼收到這個錯誤：

def GPlag(text,encode=False): 
     import urllib, urllib2, json 

     if encode == True: 
      text = text.encode('utf-8') 

     query = urllib.quote_plus(text) 
     base_url = 'http://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=' 
     url = base_url + '%22' + query + '%22' 
     request = urllib2.Request(url,None) 
     response = urllib2.urlopen(request) 
     result = json.load(response) 
     output = [] 

     if result['responseData']['results'] != []: 
      firstMatch = result['responseData']['results'][0] 
      output.append(firstMatch['title']) 
      output.append(firstMatch['visibleUrl']) 
      output.append(firstMatch['content']) 

     return output 

     def callGPlag(n): 
      for s in n: 
       outcome = GPlag(s,encode=True) 

它給出;

TypeError: 'NoneType' object has no attribute '__getitem__' 

在這if result['responseData']['results']行。這裏是回溯：

Traceback (most recent call last): 
... in <module> GPlagFile(sys.argv[1]) 
... in GPlagFile outcome = GPlag(s,encode=True) 
... in GPlag if 'results' in result['responseData']: 
TypeError: argument of type 'NoneType' is not iterable 

Answer 1

將行：

if result['responseData']['results'] != []: 

通過

if (len(result) and 
    'responseData' in result and 
    'results' in result['responseData'] and  
    result['responseData']['results'] != []):