Questions tagged [data-retrieval]
Data retrieval involves extracting the wanted data from a dataset.
464
questions
69
votes
3
answers
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What information can we access from the client? [closed]
I'm trying to compile a list of information that is accessible via javascript such as:
Geo-location
IP address
Browser software
Exit location
Entrance location
I understand that a user can alter any ...
- 13.3k
56
votes
2
answers
82k
views
How do I link each user to their data in Firebase?
I plan to create a main tree named users which will include the name different users used as username. So, from each username will be included their data e.g. Full Name, Address, Phone No.
I want to ...
- 1,629
42
votes
10
answers
107k
views
view config getter callback for component 'div' must be a function (received 'undefined'). Make sure to start component names with a capital letter
Error is: Invariant Violation: view config getter callback for component 'div' must be a function (received 'undefined'). Make sure to start component names with a capital letter.
I am getting this ...
- 523
19
votes
5
answers
37k
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Saving data upon closing app and retrieving that data
I know, there are plenty of questions in regards to saving/retrieving data on here. I was doing find looking things up on my own and really thought I could manage to find my answers without having to ...
- 1,108
17
votes
3
answers
16k
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How do I calculate TF-IDF of a query?
How do I calculate tf-idf for a query? I understand how to calculate tf-idf for a set of documents with following definitions:
tf = occurances in document/ total words in document
idf = log(#...
- 437
16
votes
1
answer
17k
views
How to evaluate a search/retrieval engine using trec_eval?
Is there any body who has used TREC_EVAL? I need a "Trec_EVAL for dummies".
I'm trying to evaluate a few search engines to compare parameters like Recall-Precision, ranking quality, etc for my ...
- 161
10
votes
5
answers
829
views
What is the point of salt and hashing if database is accessible?
I just learned the concept of hashing ("Hey! don't forget the salt!") and using salt to make the password secured.
Hashing it is a one way encryption (actually not encryption but hashing) so it ...
- 29.7k
9
votes
10
answers
6k
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How to avoid many database round trips and a lot of irrelevant data?
I have worked with various applications and encountered this situation many times. Until now I have not figured out what is the best approach.
Here's the scenario:
I have an application either ...
- 29.7k
7
votes
2
answers
3k
views
idf has no effect on ranking one term queries
I was reading through this article and it said that
Note that IDF is dependent on the query term (T) and the database as a
whole. In particular, it does not vary from document to document.
...
- 742
5
votes
1
answer
8k
views
How to retrieve all the entries with hash key as a particular pattern in dynamo DB?
I am new to amazon web services. I want to retrieve all the entries in the dynamo DB table which have a particular word in their hash key. It is similar to using like operator in oracle DB. How can I ...
- 843
5
votes
5
answers
14k
views
Extracting jpegs from a disk dump
I've got a 16GB memory card off someone that won't load properly (asks to be reformatted). I'm trying to get jpegs off it.
I've run dd to dump the contents to a file, which worked splendidly. The ...
- 72.5k
5
votes
3
answers
13k
views
LINQ to SQL Storing query results in a variable
For example I am searching for a specific persons ID and I want to store that ID to a local variable or instance variable. How do I retrieve Query results and stores them in a int Variable with LINQ ...
- 15.9k
5
votes
0
answers
689
views
Get data from android notification
I am trying to extract some data from an android notification.
When I receive a mail, I can get the name of the sender from the title attribute and the rest of the notification is in the text ...
- 53
4
votes
2
answers
6k
views
Get data of a document in firestore by giving a field value belonged to that document using Python?
I'm new to python. I'm using a firebase firestore database for this project. After entering the Admission_No, I want to retrieve all the data in the relevant document such as name, grade, phone. I ...
- 130
4
votes
1
answer
1k
views
How to retrieve float from Firestore?
Hi I have problem with retrieving data from Firestore. I don't know how to retrieve data from number field with dot.
For example Prize : 2.54
I tried this
longPrize = documentSnapshot.getLong("...
- 139
4
votes
1
answer
9k
views
Firebase Analytics - Failed to retrieve Firebase Instance ID
I´m trying to implement Firebase Analytcs into my app.
But I can´t see any data at Debugview or Dashboard.
In log I can see a message "W/FA: Failed to retrieve Firebase Instance ID"
I don't know if ...
- 363
3
votes
1
answer
938
views
How to retrieve values after a hash collision
I have read in many places that after a hash collision in Java it is internally using a linked list/tree, based on the number of hash collisions.Till this is fine,
But how to retrieve back the ...
- 77
3
votes
2
answers
2k
views
Python script that notifies me when a update is made to a website.
I need to make a script that will notify me when a change is made to a website. I am not sure about the best way to go about this and I don't know what python has that will be useful. Any push in the ...
- 1,229
3
votes
3
answers
2k
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Urllib urlopen/urlretrieve too many open files error
Problem
I'm trying to download >100.000 files from a ftp server in parallel (using threads). I previously tried it with urlretrieve as answered here, however this gave me the following error: ...
- 2,008
3
votes
2
answers
6k
views
PHP Resource ID error
I want to retrieve or output data in the database but I kept on getting the error called "Resource ID".
Here is my code:
<?php
$host="localhost";
$username="root";
$password ="123192";
$...
- 679
3
votes
3
answers
42k
views
TypeError: undefined is not an object (evaluating..)
In console before render() this.state.data1.length is not giving any error but as soon as I use it in view tag this is giving error as :
TypeError: undefined is not an object (evaluating '_this.state....
- 523
3
votes
1
answer
402
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Retrieving Data from the BattleNet
I have seen sites like "sc2ranks.com" and I totally wonder how they get information I could only access when being ingame.
I mean how can I access for example the StarCraft II EU Ladder?
Is this just ...
- 3,454
3
votes
3
answers
3k
views
Retrieve images in recyclerview from Firebase Firestore
I am trying to retrieve images from Firebase Firestore. I am able to retrieve text in RecyclerView successfully however I'm not sure how to retrieve the images.
I had a look at similar questions ...
- 75
3
votes
1
answer
514
views
How to correct my Naive Bayes method returning extremely small conditional probabilities?
I'm trying to calculate the probability that an email is spam with Naive Bayes. I have a document class to create the documents (fed in from a website), and another class to train and classify ...
- 437
3
votes
2
answers
5k
views
How to store Multiple Pieces of Data in jsTree nodes using a Single Attribute?
In order to store arbitrary data in jsTree nodes, I'm passing a custom attribute (say node-data) to the create_node method. But I need to store more than one piece of data in the single attribute. (...
- 13.1k
3
votes
4
answers
861
views
Sporadically Slow Calls From .NET Application To SQL Server
I have a table in SQL Server that I inherited from a legacy system thats still in production that is structured according to the code below. I created a SP to query the table as described in the code ...
Greg
3
votes
0
answers
1k
views
Displaying data from firestore into bootstrap HTML table
I want to display data from my CoverTransaction collection into a bootstrap table. Although the data is retrieved correctly(displayed in console) but the bootstrap features like show entries, ...
- 31
3
votes
1
answer
1k
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How do you get specific firebase data without knowing the unique id?
I have some data in my firebase database that I want to retrieve. I did one big push so that all instances would have a unique id. I know want to retrieve this data
I know I can do this:
var gymData ...
- 7,273
2
votes
3
answers
4k
views
post data from table row like json format
this is related to my last question(
NOTE: I already got some good answers there). I'm doing a program that will filter. I didn't include this question because i thought that it is easier for me to ...
- 839
2
votes
2
answers
4k
views
Doesn't retrieve the records while viewing a ResultSet in JDBC [duplicate]
Now i m learning ResultSet types in java. Here, I've coded for viewing records in different ways. At first i displayed the whole records which is in emp4 table and then i started to view these records ...
- 9,486
2
votes
1
answer
2k
views
Storing Bash associative arrays
I want to store (and retrieve, of course) Bash's associative arrays and am looking for a simple way to do that.
I know that it is possible to do it using a look over all keys:
for key in "${!arr[@]}"...
- 58k
2
votes
1
answer
16k
views
How to download a file from a URL in C, as a browser would?
I want to download a file from a URL, this one : http://download.finance.yahoo/d/quotes.csv?s=YHOO+GOOG+MSFT&f=sl1d1t1c1hgvbap2
When i go on my browser and input this URL in my browser, the file ...
- 463
2
votes
2
answers
828
views
Populating Tableviews with Images in Firebase
I recently asked this question: Populating a UITableView in Firebase a Set Number of Cells at a time
But through the discussion I realized that the question was actually two questions, so I'm going ...
- 735
2
votes
1
answer
146
views
Problem with specific fields while querying mongoDB
The problem is with these two fields : Relative Time(h:min:s.ms) and Real time(h:min:s.ms)
The values cannot be retrieved While trying to export the collection to csv/json. So I tried the following:
...
- 966
2
votes
2
answers
920
views
How to fetch multiple rows from fire store and display in Data Table --FLUTTER
I have a collection on firestore named "CASHOUT" having fields Random1,2 and 3.
which I am able to fetch and display successfuly in Data table widget
But when I created another document ...
- 91
2
votes
1
answer
460
views
What is the most efficient way to store a set of points (embeddings) such that queries for closest points are computed quickly
Given a set of embeddings, i.e. set of [name, vector representation]
how should I store it such that queries on the closest points are computed quickly. For example given 100 embeddings in 2-d space, ...
- 158
2
votes
1
answer
10k
views
retrieving data with mongodb java driver 3.4 using find()-method with projection
I am using mongodb java driver 3.4.
In the mongodb database documents are saved according to the following structure:
{
"_id" : ObjectId("595a9fc4fe3f36402b7edf0e"),
"id" : "123",
"...
- 3,549
2
votes
1
answer
3k
views
Recover Data from a corrupted LVM after lvreduce?
I'm using an Ubuntu 13.04 server.
I wanted to reduce a logical volume, in order to increase another one.
The logical volume I wanted to reduce had a size of 100G and 69G used.
I tried to reduce a ...
- 225
2
votes
2
answers
1k
views
Unable to retrieve createdAt values from Parse objects
I cannot get the createdAt value from Parse for each object.And I dont want to have to save an additional timestamp as a String when the data is sitting right there.
This is the list of what i was ...
- 105
2
votes
1
answer
222
views
merging certain attributes in datomic query results
So I have some posts that get tagged, and I'd like users to be able to add tags, and then I'd like to be able to do a query and get an aggregated list of tags for particular posts. (Currently the ...
- 5,558
2
votes
2
answers
1k
views
Read tuple key and value
How can I read a tuple key and value in Erlang?
I have this variable:
Params = [<<"TPUIBrowser">>,0,18,
{[{<<"End">>,<<"location-1ÿ">>},{<<"Start">>,...
- 9,343
2
votes
1
answer
1k
views
Windows phone 7: post some values, retrieve the response
How can I post a value to an online page, and then retrieve the response to put it in a string?
It's a PHP page that take the $_POST value and then echo a response that I want to grab.
- 611
2
votes
2
answers
866
views
GridView and objectDataSource
I have a grid view that bounded to an object data source that select data from type of student
public class student
{
int id;
string name;
int age;
public List<students> ...
- 9,296
2
votes
1
answer
62
views
What's the increment operator doing here and how it changes the scale?
What's the increment operator doing above inside the forEach block, specifically:
d3.tsv('data.tsv', (err, data) => {
// clean the data
data.forEach(d => {
d.date = new Date(d.date); //...
- 139
2
votes
1
answer
1k
views
Firebase unable to retrieve value to class
I have a working line of code retrieving each single data, but failed to apply them all to a class. This line is working perfectly.
double value = (double) ds.child("player1score").getValue();
But ...
- 87
2
votes
2
answers
2k
views
Firebase and AngularJS, How to retrieve a value from a firebaseArray
It seems to be very very simple. But I can't do it.
I just want to get a value of my Firebase DB in my controller.
The Firebase Database is like this:
users {
30549545 {
name: "Marcelo"
...
2
votes
1
answer
2k
views
MongoDB (mongoose) retrieve substring
Let's say I have a blog with some very long posts.
So, I want to display a list of my posts in "preview mode", for instance only first 50 chars of text.
Simple answer is to do this:
Post.find(
(...
- 671
2
votes
1
answer
912
views
Best way to gather data from a website for an Android application
I'm trying to put together a new app for a project that will display train times for the user.
I know there are a couple of ways to go about this, but before I get started I wanted to get some help ...
- 23
2
votes
1
answer
4k
views
Android - Retrieving a string from a specific element of a gridview
I'm pretty new to Android and I have been playing about with GridView. I've got stuck trying to retrieve Strings from individual elements of the GridView so that I can save state based on the changes ...
- 23
2
votes
1
answer
513
views
There is a problem I am facing while getting data from firebase I am getting empty array
I am facing an error while I am retrieving data from firebase. I am using React JS and Firebase Firestore for data storeing.
The problem is when I use the useEffect() hook to get data at the start of ...
