indexing

问题 Is there a pandorable way to get only the index in dataframe slicing? In other words, is there a better way to write the following code: df.loc[df['A'] >5].index Thanks! 回答1: Yes, better is filter only index values, not all DataFrame and then select index: #filter index df.index[df['A'] >5] #filter DataFrame df[df['A'] >5].index Difference is in performance too: np.random.seed(1245) df = pd.DataFrame({'A':np.random.randint(10, size=1000)}) print (df) In [40]: %timeit df.index[df['A'] >5] 208

问题 When I run my project in Netbeans 6.8, it loves to open the index page automatically. It's annoying because I always keep a tab with the page I'm working on when I work, so I don't need this index page. It also makes my current page lose focus. I have tried not specifying an index or my project URL, but then I can't run or save my project. How can I prevent it from doing so? 回答1: In NetBeans 7.4: Right-click your project, select 'Properties' In left hand pane of popup, select 'Run

问题 This question already has answers here : How do you reindex an array in PHP? (19 answers) Closed 3 years ago . Forgive my noobness again. I've got an array with 20+ values in it and I take every 20 to shove in my database and then chop them off the front of the array. I want to restart the array's indexes back to 0 but instead it starts at 20 even when I use array_values. I also tried array_merge(array(), $string) What to do? if($x%20 == 0){ var_dump($string) // original array get_string(

问题 I am writing a code which reads data from a text file. I load the data using numpy loadtxt and it could look like something like this: import numpy as np Shop_Products = np.array(['Tomatos', 'Bread' , 'Tuna', 'Milk', 'Cheese']) Shop_Inventory = np.array([12, 6, 10, 7, 8]) I want to check some of the products I have: Shop_Query = np.array(['Cheese', 'Bread'] Now I would like to find these "items" indeces in the Shop_Products array without doing a for loop and if checks. I wondered if it could

问题 I am trying to remove the last occurrence of a character in a string. I can get its index : str.lastIndexOf(',') I have already tried to use split and the replace function on the string. 回答1: You could use patch . scala> val s = "s;dfkj;w;erw" s: String = s;dfkj;w;erw scala> s.patch(s.lastIndexOf(';'), "", 1) res6: String = s;dfkj;werw 回答2: scala> def removeLast(x: Char, xs: String): String = { | | val accumulator: (Option[Char], String) = (None, "") | | val (_, applied) = xs.foldRight

问题 I want to take a column indexed 'length' and make it my second column. It currently exists as the 5th column. I have tried: colnames = big_df.columns.tolist() # make index "length" the second column in the big_df colnames = colnames[0] + colnames[4] + colnames[:-1] big_df = big_df[colnames] I see the following error: TypeError: must be str, not list I'm not sure how to interpret this error because it actually should be a list , right? Also, is there a general method to move any column by

问题 I am trying to get likers for some artists through an index on Name : START n=node:Artist(Name =~ 'Michael*.') MATCH n<-[:LIKES]-liker return liker.Id, n.Label LIMIT 50 And I have this error : Invalid query string literal or parameter expected "START n=node:ArtistId(Name =~ 'Michael*.')" I am wondering how can I use regex in index query? I know I can use regex in match but I don't know how can I use regex in START. Thanks for your help 回答1: You can't use normal regex syntax, but you can use

问题 I've got a table that refuses to use index, and it always uses filesort. The table is: CREATE TABLE `article` ( `ID` int(11) NOT NULL AUTO_INCREMENT, `Category_ID` int(11) DEFAULT NULL, `Subcategory` int(11) DEFAULT NULL, `CTimestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, `Publish` tinyint(4) DEFAULT NULL, `Administrator_ID` int(11) DEFAULT NULL, `Position` tinyint(4) DEFAULT '0', PRIMARY KEY (`ID`), KEY `Subcategory` (`Subcategory`,`Position`,`CTimestamp`,`Publish`), KEY `Category_ID

问题 I want to write a SpringBatch Tasklet, that automatically activates or de-activates all indexes for a given database table. The code needs to work independantly of the DBMS (SQL Server, Oracle and HSQLDB are required). This is what I have tried so far: DatabaseMetaData dbMetaData = connection.getMetaData(); ResultSet rs = dbMetaData.getIndexInfo(null, null, tableName, true, false); while (rs.next()) { // work with ResultSet } However, I do not get the names of the Indexes or any useful

问题 A project I've been working for 2 months stopped working for no reason because Xcode got stucked on "Indexing". I can't Build the project anymore. If I try to build, Xcode freezes and I have to force quit. This happens only with this project. I tried cleaning all derived data but didn't help. I'm using Xcode 4.5.2. Any ideas? 回答1: Open your Project Folder. Find ProjectName.xcodeproj file. Right-Click Copy and Paste to Safe Place. Right-Click Show Package Contents. Find project.xcworkspace