Question

我的问题更清楚：我使用的是mongodb，集合中的每个文档都是：

{
  u'cell_latlng': {
    u'type': u'Polygon',
    u'coordinates': [
      [
        [
          ...
        ],
        [
          ...
        ],
        [
          ...
        ],
        [
          ...
        ]
      ]
    ]
  },
  u'self': {
    u'Bus Line': 1,
    u'Meeting Room': 1,
    u'Neighborhood': 1,
    u'Home (private)': 1,
    u'Food': 1,
    u'High School': 2,
    u'Elementary School': 1,
    u'Beach': 1,
    u'Other Repair Shop': 1
  },
  u'_id': ObjectId('5545bed4e139c7dcde660f5a'),
  u'point_latlng': {
    u'type': u'Point',
    u'coordinates': [
      ...
    ]
  },
  u'area': 100
}

现在我需要在集合中找到一个特定的文档（该集合称为citymap）。我知道字段'self'的值，这个值叫做feature [0]，所以我只使用：

results = citymap.find({'self':feature[0]})

然而，

results.count() == 0

我再次检查功能[0]，我确信它是：

feature[0] = {u'Bus Line': 1, u'Meeting Room': 1, u'Neighborhood': 1, u'Home (private)': 1, u'Food': 1, u'High School': 2, u'Elementary School': 1, u'Beach': 1, u'Other Repair Shop': 1}

这与doc中的完全相同，为什么我不能用这句话找到这个doc？

非常感谢任何帮助

Answer 1

让我们检查一下这个脚本。假设你的java.lang.RuntimeException: java.lang.NullPointerException at com.intellij.idea.IdeaApplication.run(IdeaApplication.java:178) at com.intellij.idea.MainImpl$1$1$1.run(MainImpl.java:52) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:312) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:738) at java.awt.EventQueue.access$300(EventQueue.java:103) at java.awt.EventQueue$3.run(EventQueue.java:699) at java.awt.EventQueue$3.run(EventQueue.java:697) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:708) at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:362) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138) at java.awt.EventDispatchThread.run(EventDispatchThread.java:91) Caused by: java.lang.NullPointerException at com.android.tools.idea.welcome.AndroidVirtualDevice.<init>(AndroidVirtualDevice.java:81) at com.android.tools.idea.welcome.InstallComponentsPath.createComponentTree(InstallComponentsPath.java:89) at com.android.tools.idea.welcome.InstallComponentsPath.init(InstallComponentsPath.java:215) at com.android.tools.idea.wizard.DynamicWizardPath.attachToWizard(DynamicWizardPath.java:97) at com.android.tools.idea.wizard.DynamicWizard.addPath(DynamicWizard.java:233) at com.android.tools.idea.welcome.FirstRunWizard.init(FirstRunWizard.java:75) at com.android.tools.idea.welcome.FirstRunWizardHost.setupWizard(FirstRunWizardHost.java:100) at com.android.tools.idea.welcome.FirstRunWizardHost.getWelcomePanel(FirstRunWizardHost.java:92) at com.intellij.openapi.wm.impl.welcomeScreen.WelcomeFrame.<init>(WelcomeFrame.java:68) at com.intellij.openapi.wm.impl.welcomeScreen.WelcomeFrame.showNow(WelcomeFrame.java:173) at com.intellij.idea.IdeaApplication$IdeStarter.main(IdeaApplication.java:302) at com.intellij.idea.IdeaApplication.run(IdeaApplication.java:172) ... 16 more对象是这样的

feature

迭代var feature = {u'Bus Line': 1, u'Meeting Room': 1, u'Neighborhood': 1, u'Home (private)': 1, u'Food': 1, u'High School': 2, u'Elementary School': 1, u'Beach': 1, u'Other Repair Shop': 1}个对象并将每个键附加为feature并将它们推入新对象。检查以下功能：

self

现在，如果您键入var appendSelf = {}; function appendData(data) { for (var k in data) { if (data.hasOwnProperty(k)) { appendSelf["self.".concat(k)] = data[k]; //append self to every keys and set it's respective values } } }，则在控制台上将此函数调用为appendData(feature)，然后它会显示附加appendSelf的对象

self

因此，在查找条件中使用此> appendSelf { "self.u'Bus Line": 1, "self.u'Meeting Room": 1, "self.u'Neighborhood": 1, "self.u'Home (private)": 1, "self.u'Food": 1, "self.u'High School": 4, "self.u'Elementary School": 1, "self.u'Beach": 1, "self.u'Other Repair Shop": 1 }作为显示预期结果的appendSelf。

mongodb：相同的字段值，但找不到使用find（）函数

1 个答案: