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MongoDB: Combine data from multiple collections into one..how?
..., reduce;
db.users_comments.remove();
// setup sample data - wouldn't actually use this in production
db.users.remove();
db.comments.remove();
db.users.save({firstName:"Rich",lastName:"S",gender:"M",country:"CA",age:"18"});
db.users.save({firstName:"Rob",lastName:"M",gender:"M",country:"US",age:"25...
What is the difference between synchronous and asynchronous programming (in node.js)
...he next statement is run. In this case the program is evaluated exactly in order of the statements.
This is how asynchronous works in JavaScript. There are two parts in the JavaScript engine, one part that looks at the code and enqueues operations and another that processes the queue. The queue pro...
git still shows files as modified after adding to .gitignore
... His files were already tracked by git because of an earlier commit, so in order to remove them, you have to create a new commit that removes them from the repository.
– mcls
Jul 19 '16 at 5:47
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How to sort a dataFrame in python pandas by two or more columns?
... a , b and c , I want to sort the dataframe by column b in ascending order, and by column c in descending order, how do I do this?
...
Difference between Pragma and Cache-Control headers?
... Cache-Control: no-cache has the same meaning for requests but is actually also defined for responses, meaning "If you want to use a cached copy of this in future, you must first check with me that it is up-to-date (i.e. perform revalidation)".
– clime
Mar...
Best way of invoking getter by reflection
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Is there a way to invoke the methods in the order in which the fields are listed in the Java file?
– LifeAndHope
Jun 21 '15 at 19:37
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How to get a random value from dictionary in python
...b': 5}
>>> d.popitem()
('c', 7)
Since the dict doesn't preserve order, by using popitem you get items in an arbitrary (but not strictly random) order from it.
Also keep in mind that popitem removes the key-value pair from dictionary, as stated in the docs.
popitem() is useful to dest...
How do malloc() and free() work?
...ust add it to a free list that calloc() and malloc() will consult later in order to reuse the released blocks.
Even if a free() wanted to return memory to the system, it would need at least one contiguous memory page in order to get the kernel to actually protect the region, so releasing a small bl...
Regex to Match Symbols: !$%^&*()_+|~-=`{}[]:";'?,./
...
The regular expression for this is really simple. Just use a character class. The hyphen is a special character in character classes, so it needs to be first:
/[-!$%^&*()_+|~=`{}\[\]:";'<>?,.\/]/
You also need to escape the other regular expressio...
Extending Angular Directive
...d party directive. Both directives will run and you can specify their run order using the priority property (higher priority runs first).
The two directives will share scope and you can access and modify the scope of the third party directive via your directive's link method.
Option 2: You can al...