Checking whether indexes are being used in SQL query?
No, it's using an index. The ref and keylen tell us that. I think you may be confused by the Using index in the Extra column of the other rows in the EXPLAIN output. That means that the query is being satisfied entirely from the index, without a need to...
IndexError obstructing code from working with larger csv file
It is difficult without seeing the data causing the error, but try this: mode = (lambda ts: ts.value_counts(sort=True).index[0] if len(ts.value_counts(sort=True)) else None) ...
Find the sentence’s index (sentences in a list) of a specific word in Python
You can iterate over each string in the list, split on white space, then see if your search word is in that list of words. If you do this in a list comprehension, you can return a list of indices to the strings that satisfied this requirement. def f(l, s):...
R - How to re-order row index number
r,vector,indexing,data.frame,row
You can use row.names(yourdf) <- NULL to reset the row names...
Using [] on pointers in C?
In C (and also C++), array[n] is equivalent to *(array+n). They mean exactly the same thing and produce exactly the same result.
replace zero values with previous non-zero values
Try this, not sure about speed though. Got to run so explanation will have to come later if you need it: interp1(1:nnz(A), A(A ~= 0), cumsum(A ~= 0), 'NearestNeighbor') ...
PL/SQL can't put value into index by table
table,indexing,plsql,insert,value
Your TYPE emp_table is table of employees%ROWTYPE INDEX BY PLS_INTEGER; only declares a type, not an actual variable you can write into. You need to add the variable too: TYPE emp_table_type is table of employees%ROWTYPE INDEX BY PLS_INTEGER; emp_table emp_table_type; Please note I added "_type" suffix into your definition....
Finding a specific cell contanining value greater than the desired value
excel,indexing,excel-formula,vlookup
With 125 typed into D2 the first will return 101 from Range A; the second will return 500 from Range B. =INDEX(A:A, MATCH(D2, A:A)) =INDEX(B:B, MATCH(D2, A:A)) This method is known as a INDEX/MATCH function pair. When seeking approximate matches, the values to be examined must be in ascending...
What indexer do I use to find the list in the collection that is most similar to my list?
search,indexing,solr,levenshtein-distance
I wonder what keeps you from trying it with Solr, as Solr provides much of what you need. You can declare the field as type="string" multiValued="true and save each list item as a value. Then, when querying, you specify each of the items in the list to look for as...
Unable to understand the error generated
What don't you understand exactly ? The error message is quite clear: you have an IndexError (you're trying to access a non-existant item in a list, tuple or other similar indexed sequence) at line 105, which is student_grade_system = StudentGradeSystem(sys.argv[1]) In this line there's only one indexed access - sys.argv[1]...
Trying to create a new dataframe based on internal sums of a column from another dataframe using Python/pandas
python,indexing,pandas,sum,dataframes
Here is one way to avoid loop. import pandas as pd your_df = pd.DataFrame({'Col1':[1,2,3,4], 'Col2':[5,6,7,8]}) def your_func(df, column, cutoff): # do cumsum and flip over x = df[column][::-1].cumsum()[::-1] df[column][df.index > cutoff] = x[x.index > cutoff] return df # to use it your_func(your_df, column='Col1', cutoff=1) Out[68]: Col1 Col2 0 1 5...
Creating analyzed and not_analyzed index on all fields in Elasticsearch
python,indexing,elasticsearch,mapping
You can go through the document here. Using dynamic index templates , you can add rules like below and achienve the same. In the following example , I have enabled an additional field called raw ONLY if the size is less than 256 which would be not_analyzed. { "mappings": {...
How to use all the cores of Solr in solrj
java,indexing,solr,lucene,solrj
here in your code it still points to core1. HttpSolrClient solrClient = new HttpSolrClient("http://localhost:8983/solr/core1" In case you want to have the indexex for core2 you need to change here HttpSolrClient solrClient = new HttpSolrClient("http://localhost:8983/solr/core2" after this change try run the job, it will index for the core2....
How can I access semi-sparse data efficiently in java?
From what you've described here you can use HashMap<Integer, Node> or HashMap<Long, Node> depending on the range of ids you have. Depending on your other requirements LinkedHashMap and TreeMap might be alternatives (LinkedHashMap if you need to iterate over the nodes in the order that they were inserted and TreeMap...
Create a text index on MongoDB schema which references another schema
javascript,node.js,mongodb,indexing,mongoose
I think, what you are looking for is the ability to join tables of data and perform a query against the sum of that data. That is something you need a relational database for, which MongoDB isn't. So I recommend you change your approach in how you would like to...
Delete ndb EntitiesByProperty index table
google-app-engine,indexing,gae-datastore,app-engine-ndb
Yes, you'll have to re-put all of your entities in order to update the values in the indexes (or remove them, as you're asking)
How to force use of indices in MongoDB?
The notablescan ( http://docs.mongodb.org/manual/reference/parameters/#param.notablescan ) option for the MongoDB binary (mongod.exe or mongod depending on your OS) allows you to stop any query, with an emitted log error, which does not use an index at all. This option will not stop inefficient queries though so that part will still need...
Do index names have to be unique across entire database in Mysql?
Yes you can use same index name for both the tables. CREATE [UNIQUE|FULLTEXT|SPATIAL] INDEX IDnum [index_type] ON tbl_name (index_col_name,...) [index_type]...
Numpy Indexing: Get every second coloumn for each even row
Okay if we can not avoid any copy, than the easiest thing to do would be probably something like: a = np.arange(16).reshape(4,4) array([[ 0, 1, 2, 3], [ 4, 5, 6, 7], [ 8, 9, 10, 11], [12, 13, 14, 15]]) b = np.zeros((a.shape[0], a.shape[1]/2)) b[::2,:] = a[::2,1::2] b[1::2,:] =...
SQL - Avoid 2 columns in 1 record having the same value
Normally you would use a CHECK constraint for that. Bu MySQL does currently not support them. It accepts the input but ignores them. But you can use a trigger that cancels the insertion/update on certain conditions like this delimiter // CREATE TRIGGER check_trigger BEFORE INSERT ON your_table FOR EACH ROW...
System.ArgumentOutOfRangeException in For loop due to entry deleted from database. Help fix it
database,vb.net,for-loop,indexing
Try going backwards - For i As Integer = (.Rows.Count - 1) to 0 Step -1. The issue is that you are deleting rows in the ReservationTableDataGridView as you try to iterate over them, thus changing the index. By going backwards you always have a valid index....
retrieve Hashmap Elements by index based
First of all, you will have to use LinkedHashMap. Map pins = new LinkedHashMap(); and then after putting in the values, you can do the following: List keys = new ArrayList(pins.keySet()); List values = new ArrayList(pins.values()); System.out.print((String)keys.get(0) + " " + (String)values.get(0)); ...
Converting MATLAB to Python: too many indices return error
python,arrays,matlab,numpy,indexing
It looks like index is a 1-d array? (you have index[y] and index[x] on line 5 and 8, and say it is of length 16) But, on line 11, you are trying to access its second dimension: index[y,:]. Maybe that should be indexdn[y,:] =-indexdn[:,y]?...
Python: How to index the elements of a numpy array?
Given that your desired output is a dictionary, I don't think there's going to be an efficient way to do this with NumPy operations. Your best bet will probably be something like import collections import itertools d = collections.defaultdict(list) for indices in itertools.product(*map(range, a.shape)): d[a[indices]].append(indices) ...
Why iterative loop to remove items in list stops
list,python-2.7,loops,indexing
To understand why this is happening, let us look step-by-step what is happening internally. Step 1: >>> foo = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'] Here, a new list object is created and is assigned to foo. Step 2: >>> for i in foo: Now, the iteration starts....
python compare items in 2 list of different length - order is important
python,list,loops,for-loop,indexing
Use the zip() function to pair up the lists, counting all the differences, then add the difference in length. zip() will only iterate over the items that can be paired up, but there is little point in iterating over the remainder; you know those are all to be counted as...
Referencing numpy array locations within if statements
python,arrays,matlab,numpy,indexing
Looks like index is an array of some sort, but when you do index(y) and index(x), Python thinks you're trying to call a function index() using x and y as parameters, respectively. If you're trying to simply access the elements, use index[x] and index[y]....
Proper if..else syntax in Python
python,if-statement,indexing,operand
The correct syntax is if condition: # stuff elif other: # stuff elif some_other: # stuff else: # stuff Note that else does not get any explicit condition, it is the catch-all if none of the above conditions were True....
Creating Index in Elasticsearch using Java API giving NoClassFoundException
ES 1.5.2 uses Lucene 4.10.4. Get the jars you need from here. Note that you might need not only lucene-core but others as well. Just browse the Maven repo and look for other jars as well, but all should be version 4.10.4.
Get specific values form JSON Table with javascript over IDs
javascript,arrays,json,indexing
You are almost correct. Restructure your array into an associative array of associative arrays. You can call them by array_name['first_index']['second_index']. var testext = { "key1": { "firstName": "Ray", "lastName": "Villalobos", "joined": 2012 }, "key2": { "firstName": "John", "lastName": "Jones", "joined": 2010 } }; document.getElementById("demo").innerHTML = testext['key1']['firstName']; <div id="demo">Default</div> ...
Lucene get all non deleted document from index file
Lucene provides a bitset of all non-deleted documents, called liveDocs. You can get it by iterating over all LeafReaders (or using the SlowCompositeReaderWrapper) and calling the liveDocs method or by using the MultiFields class. Once you have this bitset, you can iterator from 0 to IndexReader#maxDoc and consult the bitset...
ElasticSearch- “No query registered for…”
Write your query like this, i.e. sort needs to go to the top-level and not nested in the querypart: { "query": { "filtered": { "query": { "query_string": { "fields": [ "description" ], "query": "sun" } }, "filter": { "term": { "permissions": 1 } } } }, "sort": [ { "likes_count":...
Why does my array lose its mask after doing multidimensional indexing in Numpy?
python,numpy,multidimensional-array,indexing
Looks like indexing with a masked array just ignores the mask. Without digging much into the docs or code, I'd say the numpy array indexing has no special knowledge of the masked array subclass. The array you get is just the normal arange(20) indexing. But you could perform normal indexing,...
python and arduino : list index out of range err
Others have tried to answer the question - but I think the basic confusion is not resolved line[:-5] will remove last 5 characters from a line For example if your line is 'abcdefghijklm' then line[:-5] would give 'abcdefgh'. Now let's look at your adruino code specifically following line Serial.print(id_lum) Now...
Python: How to check the value of a non-existent list element without getting IndexError?
python,list,if-statement,indexing,indexoutofboundsexception
Just test if there are enough elements: x = 'foo' if len(myList) > 2 and myList[2] is not None else 'bar' It doesn't matter if the first 2 elements are missing or if you have more than 3 elements. What matters is that the list is long enough to have...
Search for nodes in Neo4j with schema index
As of today schema indexes just support exact matches, e.g. MATCH (p:Person) WHERE p.name='abc' or IN operators MATCH (p:Person) WHERE p.name in ['abc','def'] Future releases might have support for wildcards as well....
Decision to use KEY or UNIQUE KEY
Both unique and non-unique indexes result in I/O operations for INSERT, DELETE, and UPDATE statements. The amount of index overhead should be pretty much the same. The difference is that unique indexes might result in a failure of an INSERT or UPDATE under normal use (of course, the operations might...
Python numpy bool masks for absoluting values
python,arrays,numpy,indexing,masking
Firstly, you could instantiate your array directly using np.random.randint: # Note: the lower limit is inclusive while the upper limit is exclusive x = np.random.randint(-5, 6, size=(5, 5)) To actually get the job done, perhaps type-cast to bool, type-cast back, and then negate? res = 1 - x.astype(bool).astype(int) Alternatively, you...
Indexing cannot yield multiple results in MATLAB
matlab,indexing,confusion-matrix
This error tells me that you've defined a variable max somewhere in your code. Indexing cannot yield multiple results Why? Because otherwise [Max, argmax1]= max(simoutelem); wouldn't be taken as a case of "Indexing". Easy proof at command line: [a b] = max([1 2 3 4 5]) % works max =...
Fast indexing using multiple ES nodes?
java,indexing,elasticsearch,lucene,scalability
Answer1: No. The speed of indexing will in fact decrease if you enable replication (though it may increase search performance). You can look at this question for improving indexing performance. Answer2: It depends (if no replica then same). During indexing the data will go only to data nodes. Your cluster...
Printing corresponding elements from multiple lists by using known element from a single list in Python
Looks like you can use the numpy where function: //Set i to be index of h in data i = numpy.where(data==h) ...
Jquery/javascript named index array with array association
javascript,jquery,arrays,indexing,named
I want to know if its possible... Yes, although the way you're using it, you wouldn't want an array, you'd just want an object ({}) (see below). ...(and correct)... Some would argue that using an array and then adding non-index properties to it is not correct. There's nothing technically...
Pandas: break categorical column to multiple columns
You could use set_index to move the type and id columns into the index, and then unstack to move the type index level into the column index. You don't have to worry about the v values -- where the indexes go dictate the arrangement of the values. The result is...
Python `dict` indexed by tuple: Getting a slice of the pie
python,dictionary,indexing,tuples
The way your data is currently organized doesn't allow efficient lookup - essentially you have to scan all the keys. Dictionaries are hash tables behind the scenes, and the only way to access a value is to get the hash of the key - and for that, you need the...
Lucene vs Solr, indexning speed for sampe data
java,indexing,solr,lucene,full-text-search
Solr is a general-purpose highly-configurable search server. The Lucene code in Solr is tuned for general use, not specific use cases. Some tuning is possible in the configuration and the request syntax. Well-tuned Lucene code written for a specific use-case will always outperform Solr. The disadvantage is that you must...
How to count the characters of each line in a string and convert the number to a hex
String msg = "Bruce Wayne,Batman,None,Gotham City,Robin,The Joker\n" + "Oliver Queen,Green Arrow,None,Star City,Speedy,Deathstroke\n" + "Clark Kent,Superman,Flight,Metropolis,None,Lex Luthor\n" + "Bart Allen,The Flash,Speed,Central City,Kid Flash,Professor Zoom"; String[] lines = msg.split("\n"); for(Integer i = 1; i <= lines.length; i++){ int numChars = 0; String[] toks = lines[i - 1].split(","); for(String tok : toks){ numChars...
Postgres tsearch performance on first query
performance,postgresql,indexing,full-text-search,ispell
It is known problem - loading ispell dictionary is slow (it is loaded every time when dictionary is used first time in session). One and good solution is session pooling. Other solution is using shared ispell dictionary - extension that was written by Tomas Vondra - shared_ispell, but I don't...
PHP Autoincrement Array
php,arrays,indexing,key,key-value
You may consider using for() and array_push() function. Schematic code could look like this: $paymentsArray = array(); $day = "27"; $month = "05"; $year ="2015"; for($i=0; $i <= $PaymentCounts; $i++) { array_push($paymentsArray, array('Amount1' => "100.00", 'AmountDate1' => "$day.$month.$year")); $month++; } $arr = array ('Client' => "Alex", 'BillNumber' => "123", 'PaymentCounts'...
Which tables do not have indexes in Oracle? [closed]
Well, normally I wouldn't do this, but here you go: SELECT t.TABLE_NAME FROM USER_TABLES t LEFT OUTER JOIN (SELECT DISTINCT TABLE_NAME FROM USER_INDEXES) i ON i.TABLE_NAME = t.TABLE_NAME WHERE i.TABLE_NAME IS NULL; Perhaps your question should be "Why did someone just do my homework for me?". Best of luck....
Covering index and getting rid of Key Lookup
The problem is that your index can't really be used for the join. To be usable, the first field(s) in the index must be such that you're also joining the table with (or exist in the where clause). INNER JOIN exception AS ex ON ed.exceptionDefId = ex.exceptionDefId AND ex.loanId IS...
php not executing in a get_file_contents document
Is it possible to share the code which is in footer.php and confirm that how you are including the file
Manipulate a matrix based on another matrix
Here a solution using a For loop statement. Let me know if this correspond to what you are looking to do: idxList = []; for ii = 1:size(est,1) if k(ii,1) == 0 idxList = [idxList ii]; end end est(idxList) = []; The code makes a list of index for all...
Why MongoDB doesn't uses Index Intersection?
mongodb,indexing,database-indexes,mongodb-indexes
There are some details about the index selection in the SERVER-3071 JIRA issue but I cannot say if all is still relevant for 3.0. Anyway: MongoDB 3.0.2 seems not consider index interaction for range query. But it will for point intervals: > db.orders.find( { item: {$eq : "abc123"}, qty: {...
Reduction of list dimensions in Python
Change your last line to: nodeclass[k].extend(nodeindex) The two extra list wrappings you're creating are happening in: The list comprehension inside the indices function. The [nodeindex] wrap in the append call. ...
Subsetting and Indexing in For Loop in R
If you wanted to get the n smallest values in a dataset sorted by rank, you can do this with the order and head functions -- no need for the for loop: num <- 10 head(df[order(df$Rank),], num) # State City Value Rank # 7 State1 city7 0.1075155728 1 # 19...
Access data.table columns with strings
You can use get() as the j argument using single brackets: library(data.table) dt <- data.table(iris) dt[, get("Species")] The result: [1] setosa setosa setosa setosa setosa setosa ..... You can also use a string directly inside the double bracket operator, like this: dt[["Species"]] ...
Optimize the execution of select
sql-server,indexing,query-optimization,clustered-index,non-clustered-index
There's few things to consider when creating indexes, for example in this case: How many rows have Dane5 > 199850 and how many rows there are in total? Are there a lot of updates to the columns in the index -> slowness to updates. Are there going to be a...
Multidimensional List get Position of a String Python
python,string,list,indexing,set
You can create a dictionary and then return the set() of the value for a given key. Example >>> def returnSetOfList(scheme, key): ... a_dict = dict(scheme) ... return set( a_dict[key] ) ... >>> relational_scheme = [["F",["DC"]],["A",["EBD"]],["DC" , ["BAF"]],["E",["DB"]]] >>> returnSetOfList(relational_scheme, "F") set(['DC']) ...
Optimizer using an index not present in the current schema
You're connected as user ALLL, but you're querying a table in the HR schema: SELECT /*+ FIRST_ROWS(25) */ employee_id, department_id FROM hr.employees WHERE department_id > 50; You stressed other schema in the question, but seem to have overlooked that the table you're querying is also in another schema. The employees...
C# implementation of Dictionary to Create an index of words
c#,visual-studio,dictionary,indexing,text-processing
Try something like this: void Main() { var txt = "that i have not had not that place" .Split(" ".ToCharArray(),StringSplitOptions.RemoveEmptyEntries) .ToList(); var dict = new OrderedDictionary(); var output = new List<int>(); foreach (var element in txt.Select ((word,index) => new{word,index})) { if (dict.Contains(element.word)) { var count = (int)dict[element.word]; dict[element.word] = ++count;...
Postgres full text search: how to search multiple words in multiple fields?
sql,postgresql,search,indexing,full-text-search
It looks like what you want is, in fact to search the concatenation of all those fields. You could build a query doing exactly this ... where to_tsvector('italian', name||' '||coalesce(decription,'')...) @@ to_tsquery('$word') and build an index on the exact same computation: create index your_index on shop using GIN(to_tsvector('italian',name||' '||coalesce(decription,'')...)) Don't...
Problems with matrix indexing using for loop and if condition
matlab,if-statement,for-loop,matrix,indexing
You can use bsxfun to avoid for-loop (note that it is actually not vertorizing): value1 = bsxfun(@times,data(params(:,11),:),(params(:,8)==1)); value2 = bsxfun(@times,data(params(:,11),:),(params(:,8)==2)); value3 = bsxfun(@times,data(params(:,11),:),(params(:,8)==3)); But it still gives you the results with zero rows. So you can remove zero-rows by: value1(all(value1==0,2),:)=[]; value2(all(value2==0,2),:)=[]; value3(all(value3==0,2),:)=[]; You can also use above commands to remove...
Python Pandas: select rows based on comparison across rows
Try this. import pandas as pd import numpy as np index = 'A A A B B C D D'.split() col1 = [120, 90, 80, 80, 50, 120, 150, 150] ser = pd.Series(col1, index=index) # use groupby and keep the first element ser.groupby(level=0).first() Out[200]: A 120 B 80 C 120...
How can I use MySQL statement 'show index' with PDO?
are you sure it fails? what is the result of this code? $pdo = new PDO( "mysql:dbname=" . SQL_DB . ";host=" . SQL_HOST, SQL_USER, SQL_PWD, array( PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION ) ); try { $stm = $pdo->prepare("show index from `TABLENAME` where `Key_name` = 'PRIMARY'"); $res = $stm->execute(); print_r($stm->fetch(PDO::FETCH_ASSOC)); } catch (Exception...
np.argmax on multidimensional arrays, keeping some indexes fixed
numpy,multidimensional-array,indexing,argmax
This here works for me where Mat is the big matrix. # flatten the 3 and 4 dimensions of Mat and obtain the 1d index for the maximum # for each p1 and p2 index1d = np.argmax(Mat.reshape(Mat.shape[0],Mat.shape[1],-1),axis=2) # compute the indices of the 3 and 4 dimensionality for all p1...
Creating index while updating the documents
The amount of time it takes to add the index would depend on your hardware, but with 20206 records a simple index as you describe shouldn't take very long for most hardware. Queries fully covered by the index (i.e. where you specify A and B, or just A, but not...
Neo4j: configure legacy index with cypher or property file
I've written some code that might be helpful: neo4j-fti It basically hooks into the startup process and creates manual indexes with customizable analyzers. ...
Retrieve index of newly added row - for loop in R
This isn't very elegant, but it might work better than using two functions to fill in the rows and columns separately. Here, x is a list of all your matrices; factor is an optional list of desired row and column names fix_rc <- function(x, factors) { f <- function(x) factor(ul...
comparing index values in an array
ruby-on-rails,ruby,indexing,each
I think I understand what you're trying to achieve: You want to make sure that a player has a ranking between the minimum and maximum ranking, but you only store the ranking in each model as a string. The ranking array has rankings in ascending order, but I'm not sure...
How to get a mysql query to use a specific index?
If the index is appropriate it will be used without explicitly specifying it. Given you are using SELECT * I would not expect your index to be used (even if the INDEX hint had the correct syntax). The choice is down to the query optimiser's heuristics. The correct syntax is:...
Do you get the same performance using index prefixes?
A "compound index" which is the correct term for your "link" does not create any performance problems on "read" ( since writing new entries is obviously more information ) than an index just on the single field used in the query. With one exception. If you use a "multi-Key" index...
MySQL not using index when where condition have if clause
In general, databases (including MySQL) do not use indexes when columns are the arguments to functions. You could try: SELECT * FROM mytable WHERE (@type = 1 and col1 = 1420070400) or (@type <> 1 and col2 = 1420070400); But, it is unlikely that this will use an index either....
Postgres does not use an index even less than 5% rows are returned
database,postgresql,indexing,database-performance
I guess you can't reply in comments so I have to post an answer. Explain analyze showed, that your timestamp columns are compared with numeric values timestamp >= 1431093600.00 and timestamp <= 1431100800.00 and because of that they were cast to numeric: Filter: ((numvalues[1] IS NOT NULL) AND (("timestamp")::numeric >=...
Why can't I access the elements of my NSMutableArray?
objective-c,indexing,nsmutablearray
You don't put integers, or NSIntegers, into the array, but objects, i.e. instances of NSNumber. NSNumber *number = patternA[3]; long a = number.longValue; will give give you correct value. This is called boxing / unboxing - putting plain values into objects. So what you were dumping was more or less...
Lucene how to index in Database (Cassandra)
java,indexing,lucene,cassandra
It will not look like a relational database table, instead Lucene uses the inverted index and cosine similarity formula for searching of any search words. To better understand you need to look for various terminology and formula to be used in lucene, you can check out it on lucene officially...
Creating NxM indices from a Python array
From your comment: x = np.arange(25).reshape((5,5)) A = [[node0,node1,...node24], [column index for each node above from 0 to 24], [row index for each node from 0 to 24], [value for each node from 0 to 24]] One easy way to collect this sort of information would be loop like A...
MySQL performance with index clairification
Indexes have their own "tables", and when the MySQL engine determines that the lookup references an indexed column, the lookup happens on this table. It isn't really a table per-se, but the gist checks out. That said, it will be nanoseconds slower, but not something you should concern yourself with....
Postgres Index-only-scan: can we ignore the visibility map or avoid heap fetches?
There is no way to do what you want in PostgreSQL as it stands. It'd be interesting to do but a fair bit of work, very unlikely to be accepted into core, extremely hard to do with an extension, and likely to have worse side-effects than you probably expect. You'd...
Getting index of a certain element in a 2D numpy array
python,numpy,multidimensional-array,indexing,dynamic-arrays
To get the row with the highest number of non-zero cells and the highest sum you can do densities = x.sum(axis=1) lengths = (x > 0).sum(axis=1) center = x[(densities == densities.max()) & (lengths == lengths.max()] Try to avoid using loops in numpy. Let me know if this isn't what you...
Remove inf from Theano array
I found an awkward workaround import theano import theano.tensor as T import numpy as np vec = T.vector() compare = T.isinf(vec) out = vec[(1-compare).nonzero()] v = [ 1., 1., 1., 1., np.inf, 3., 4., 5., 6., np.inf] v = np.asarray(v) out.eval({var:v}) array([ 1., 1., 1., 1., 3., 4., 5., 6.])...
Looping through numbers to create a large table
For this first code block, I tried to stay with the general structure of the code in your question. I could have for example swapped out the innermost two For loops for a single While loop. That would be more efficient but requires a significant logic change. I did make...
Searching a TextField and IntField together seperated by an AND condition In Lucene
There are a few possibilities. First, what I would most recommend in this case, is perhaps you don't need those IntFields at all. Zip codes and IDs are usually not treated as numbers. They are identifiers that happen to be comprised of digits. If your zip code is 23456, that...
Postgres 9.4 jsonb array as table
sql,json,postgresql,indexing,jsonb
Query Your table definition is missing. Assuming: CREATE TABLE configuration ( config_id serial PRIMARY KEY , config jsonb NOT NULL ); To find the a value and its row for given oid and instance: SELECT c.config_id, d->>'value' AS value FROM configuration c , jsonb_array_elements(config->'data') d -- default col name is...
What can I use as an array index in GLSL in WebGL ?
In WebGL/GLES2: Yes, only constants are allowed. However if your code can be unrolled (either by yourself or by the compiler) then it counts as a constant and you have a workaround. For example, The problem: uniform int i; ... int a[4]; a[2] = 42; // ✓ a constant index,...
Variable indexes outside of defined range in AMPL
variables,indexing,set,linear-programming,ampl
In AMPL, you can create or define your own "sets" for valid indices and use them in your constraints. So, in your case, to avoid invalid indices, you can define a set of permissible indices: param inner_i {2..(N-1)} and loop over those when creating the constraints. The price we pay...
Numpy: Multidimensional index. Row by row with no loop
python,numpy,multidimensional-array,indexing,vectorization
The complicated slicing operation could be done in a vectorized manner like so - shp = A.shape out = A.reshape(shp[0],shp[1],-1)[np.arange(shp[0]),:,B[:,0]*shp[3] + B[:,1]] You are using the first and second columns of B to index into the third and fourth dimensions of input 4D array, A. With it means is, basically...
Does PostgreSQL quickly search for columns with arrays of strings?
arrays,database,performance,postgresql,indexing
GIN and GiST indexes are generally bigger than a simple b-tree, and take longer to scan. GIN is faster than GiST at the cost of very expensive updates. If you store your tags in an array column then any update to the row will generally require an update to the...
SQL Index - is this overlapping?
No, it would not be safe to remove that. The order and position of the columns is important. The introduction of the price column between the other two columns (brand and model) is the issue. Without the index on just (brand,model), the the model values are "in order" under the...
MySQL indexes performance on huge tables
mysql,sql,database,performance,indexing
For this query: SELECT MAX(YEAR(p.birthdate)) as max_year, wi.department as department FROM person p INNER JOIN works_in wi ON wi.person_id = p.id WHERE p.birthdate IS NOT NULL GROUP BY wi.department; The best indexes are: person(birthdate, id) and works_in(person_id, department). These are covering indexes for the query and save the extra cost...
Is there a way to associate data with a file in a folder hierarchy?
java,indexing,uniqueidentifier,tagging,subfolder
If you want to keep track of a file, even when its name and/or location changes, you should use its unique identifier, which in most file systems is called its inode. (I think NTFS/Windows calls it a "file ID.") You can read a file's inode using its BasicFileAttributes.fileKey: Object key...