我有一个Pandas Series对象，其日期索引和dict值如下：
timeSeries = pd.Series({'2014-05-01': {'property1': 1, 'property2': 2},
'2014-05-02': {'property1': 3, 'property2': 4}})
我知道每个dict包含相同的键（property1和property2）。有没有办法让系列没有循环只有property1作为值。
即。我想要：
propertySeries = pd.Series({'2014-05-01': 1,
'2014-05-02': 3})
答案 0 :(得分：2)
您可以values将Series转换为numpy array，然后使用DataFrame构造函数：
print (timeSeries.values.tolist())
[{'property1': 1, 'property2': 2}, {'property1': 3, 'property2': 4}]
df = pd.DataFrame(timeSeries.values.tolist(), index=timeSeries.index)
print (df)
property1 property2
2014-05-01 1 2
2014-05-02 3 4
print (df['property1'])
2014-05-01 1
2014-05-02 3
Name: property1, dtype: int64
print (df['property2'])
2014-05-01 2
2014-05-02 4
Name: property2, dtype: int64
另一个更慢的解决方案：
print (timeSeries.apply(lambda x: x['property1']))
2014-05-01 1
2014-05-02 3
dtype: int64
print (timeSeries.apply(lambda x: x['property2']))
2014-05-01 2
2014-05-02 4
dtype: int64
如果您自己创建了时间序列，请使用DataFrame.from_dict：
timeSeries = pd.DataFrame.from_dict({'2014-05-01': {'property1': 1, 'property2': 2},
'2014-05-02': {'property1': 3, 'property2': 4}},
orient='index')
print (timeSeries)
property1 property2
2014-05-01 1 2
2014-05-02 3 4
答案 1 :(得分：1)
如果您自己创建了时间序列，则可以改为创建一个DataFrame：
public class HomeActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener, PostFragment.OnPostSelectedListener, PostDialogFragment.OnPostSelectedListener, UploadMethodDialogFragment.OnImageSelectedListener {
private AlertDialog userDialog;
private ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
viewPager = (ViewPager) findViewById(R.id.viewPager);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolBar);
setSupportActionBar(toolbar);
FeedsPagerAdapter adapter = new FeedsPagerAdapter(getSupportFragmentManager());
adapter.addFragment(PostFragment.newInstance(PostFragment.TYPE_NEW), "NEW");
adapter.addFragment(PostFragment.newInstance(PostFragment.TYPE_CATEGORY), "CATEGORY");
adapter.addFragment(PostFragment.newInstance(PostFragment.TYPE_NOTIFICATION), "NOTIFICATIONS");
viewPager.setAdapter(adapter);
viewPager.setCurrentItem(0);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabLayout);
tabLayout.setupWithViewPager(viewPager);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
View header = navigationView.getHeaderView(0);
TextView navName = (TextView) header.findViewById(R.id.nav_header_name);
TextView navEmail = (TextView) header.findViewById(R.id.nav_header_email);
ImageView navProfilePicture = (ImageView) header.findViewById(R.id.nav_profile_picture);
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if (user != null) {
// Name, email address, and profile photo Url
String user_name = user.getDisplayName();
String user_email = user.getEmail();
Uri pictureURL = user.getPhotoUrl();
navName.setText("" + user_name);
navEmail.setText("" + user_email);
Glide
.with(getApplicationContext())
.load(pictureURL)
.into(navProfilePicture);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
viewPager.setCurrentItem(0);
} else if (id == R.id.nav_gallery) {
viewPager.setCurrentItem(1);
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
class FeedsPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public FeedsPagerAdapter(android.support.v4.app.FragmentManager manager) {
super(manager);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
@Override
public void onPostComment(String postKey) {
if (postKey == null) {
showAlertDialog("无法连接",
"Key : " + postKey, false);
} else {
android.support.v4.app.FragmentManager fm = getSupportFragmentManager();
CommentFragment um = new CommentFragment();
Bundle args = new Bundle();
args.putString("postKey", postKey);
um.setArguments(args);
um.show(fm, "Comment");
}
}
@Override
public void onPostLike(final String postKey) {
final String userKey = FirebaseUtil.getCurrentUserId();
final DatabaseReference postLikesRef = FirebaseUtil.getLikesRef();
postLikesRef.child(postKey).child(userKey).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
// User already liked this post, so we toggle like off.
postLikesRef.child(postKey).child(userKey).removeValue();
} else {
postLikesRef.child(postKey).child(userKey).setValue(ServerValue.TIMESTAMP);
}
}
@Override
public void onCancelled(DatabaseError firebaseError) {
}
});
}
@Override
public void onUpdateNotification(final String postKey) {
final String userKey = FirebaseUtil.getCurrentUserId();
final DatabaseReference notificationRef = FirebaseUtil.getUserNotificationsRef();
notificationRef.child(userKey).child(postKey).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
HashMap<String, Object> result = new HashMap<>();
result.put("status", false);
result.put("count", 0L);
notificationRef.child(userKey).child(postKey).updateChildren(result);
}
}
@Override
public void onCancelled(DatabaseError firebaseError) {
}
});
}
@Override
public void onPostOpenDialog(final String postKey) {
Bundle bundle = new Bundle();
bundle.putString("postID", postKey);
//set Fragment class Arguments
PostDialogFragment fragObj = new PostDialogFragment();
fragObj.setArguments(bundle);
android.support.v4.app.FragmentManager fm = getSupportFragmentManager();
fragObj.show(fm, "Post Fragment");
}
public void onPicSelected(String filePath) {
if(filePath!=null){
Bundle bundle = new Bundle();
bundle.putString("filePath", filePath);
//set Fragment class Arguments
UploadPictureDialogFragment fragObj = new UploadPictureDialogFragment();
fragObj.setArguments(bundle);
android.support.v4.app.FragmentManager fm = getSupportFragmentManager();
fragObj.show(fm, "上载图片");
}
}
public void userDetails(MenuItem item) {
// [START subscribe_topics]
FirebaseMessaging.getInstance().subscribeToTopic("6biC3YfNUiWpHqmasa4O74KPWwC2");
// [END subscribe_topics]
// Log and toast
String msg = "Subscribed to news topic";
Log.d("Subscribe", msg);
Toast.makeText(HomeActivity.this, msg, Toast.LENGTH_SHORT).show();
}
public void upload_method(MenuItem item) {
android.support.v4.app.FragmentManager fm = getSupportFragmentManager();
UploadMethodDialogFragment um = new UploadMethodDialogFragment();
um.show(fm, "Upload Method");
}
private void showAlertDialog(String title, String body, Boolean status) {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle(title).setMessage(body).setNeutralButton("好的", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
try {
userDialog.dismiss();
} catch (Exception e) {
//
}
}
});
userDialog = builder.create();
userDialog.show();
}
@Override
public void onBackPressed() {
viewPager.setCurrentItem(0);
}
}