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What's the $unwind operator in MongoDB?
...om your mind. The way that it stores your data is in the form of documents and collections, which allows for a dynamic means of adding and obtaining the data from your storage locations.
That being said, in order to understand the concept behind the $unwind parameter, you first must understand what...
svn: replace trunk with branch
...
Use svn move to move the contents of the old trunk somewhere else and rename the branch to trunk afterward.
Note that copy and move in svn work like file operations. You can use them to move/copy stuff around in your repository and these changes are versioned as well. Think of "move" as "c...
SQL Server add auto increment primary key to existing table
...lues when you do this:
ALTER TABLE dbo.YourTable
ADD ID INT IDENTITY
and then you can make it the primary key:
ALTER TABLE dbo.YourTable
ADD CONSTRAINT PK_YourTable
PRIMARY KEY(ID)
or if you prefer to do all in one step:
ALTER TABLE dbo.YourTable
ADD ID INT IDENTITY
CONSTRA...
How to use filter, map, and reduce in Python 3
filter , map , and reduce work perfectly in Python 2. Here is an example:
7 Answers
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Twitter API returns error 215, Bad Authentication Data
... to obtain following keys you need to sign up with https://dev.twitter.com and create application.
<?php
$token = 'YOUR_TOKEN';
$token_secret = 'YOUR_TOKEN_SECRET';
$consumer_key = 'CONSUMER_KEY';
$consumer_secret = 'CONSUMER_SECRET';
$host = 'api.twitter.com';
$method = 'GET';
$path = '/1.1/st...
Get top 1 row of each group
...nt to:
maintain status in 2 places
preserve status history
...
As it stands, you preserve status history. If you want latest status in the parent table too (which is denormalisation) you'd need a trigger to maintain "status" in the parent. or drop this status history table.
...
Using sed to mass rename files
...ld say that the easiest way to do this is to use the
prename or rename commands.
On Ubuntu, OSX (Homebrew package rename, MacPorts package p5-file-rename), or other systems with perl rename (prename):
rename s/0000/000/ F0000*
or on systems with rename from util-linux-ng, such as RHEL:
rename 0...
Programmatically creating Markdown tables in R with KnitR
I am just starting to learn about KnitR and the use of Markdown in generating R documents and reports. This looks to be perfect for a lot of the day to day reporting that I have to do with my job. However, one thing that I'm not seeing is an easy way to print data frames and tables using Markdown fo...
Tips for debugging .htaccess rewrite rules
Many posters have problems debugging their RewriteRule and RewriteCond statements within their .htaccess files. Most of these are using a shared hosting service and therefore don't have access to the root server configuration. They cannot avoid using .htaccess files for rewriting and cannot e...
Can Android Studio be used to run standard Java projects?
For those times when you want to isolate the Java and give it a quick test..
13 Answers
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