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Ways to implement data versioning in MongoDB
... approach would be to store diffs. Because the display of these diffs is really a special action, I would put the diffs in a different "history" collection.
I would use the different collection to save memory space. You generally don't want a full history for a simple query. So by keeping the histo...
Looping through array and removing items, without breaking for loop
...ction and the for loop both iterate over the array (splice function shifts all elements of array in the worst case). Instead you can just push the required elements to the new array and then just assign that array to the desired variable (which was just iterated upon).
var newArray = [];
for (var i...
How to create a .gitignore file
.... However, I can't find it in my project folder. Isn't it created automatically by Xcode? If not, what command allows me to create one?
...
Understanding recursion [closed]
...A binary tree is a tree made of nodes that have exactly two children, typically called "left" and "right"; again the children can be nodes, or null. A root is a node that is not the child of any other node.
Imagine that a node, in addition to its children, has a value, a number, and imagine that we...
Principal component analysis in Python
...
Months later, here's a small class PCA, and a picture:
#!/usr/bin/env python
""" a small class for Principal Component Analysis
Usage:
p = PCA( A, fraction=0.90 )
In:
A: an array of e.g. 1000 observations x 20 variables, 1000 rows x 20 colum...
Is explicitly closing files important?
In Python, if you either open a file without calling close() , or close the file but not using try - finally or the " with " statement, is this a problem? Or does it suffice as a coding practice to rely on the Python garbage-collection to close all files? For example, if one does this:
...
How to revert a Git Submodule pointer to the commit stored in the containing repository?
...or the key submodule.$name.update
is set to rebase or merge.
Run this and all should be well:
git submodule update --init
You can add the --recursive flag as well to recurse through all submodules.
share
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Difference between CouchDB and Couchbase
...erate features of CouchDB that you will not find in the Couchbase Server.
All of the names relating to CouchDB and Couchbase can be really confusing, so I've updated this answer, to begin with a brief explanation of the most important ones.
Names and confusion
There is CouchDB, CouchIO, CouchOne,...
What are JavaScript's builtin strings?
...
First of all, I would like to thank Jason and all the contributors for playing with that funny snippet. I have written that piece of code just for fun in order to send it to my wife on February 14 :) Having only Chrome installed on th...
Private and Protected Members : C++
...
Public members of a class A are accessible for all and everyone.
Protected members of a class A are not accessible outside of A's code, but is accessible from the code of any class derived from A.
Private members of a class A are not accessible outside of A's code, or f...