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Hidden features of Perl?
What are some really useful but esoteric language features in Perl that you've actually been able to employ to do useful work?
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python assert with and without parenthesis
...through IDLE. Because assert is a keyword and not a function, you are actually passing in a tuple as the first argument and leaving off the second argument.
Recall that non-empty tuples evaluate to True, and since the assertion message is optional, you've essentially called assert True when you wr...
SQL query to select dates between two dates
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You might mention that the order matters in the BETWEEN function. It has to go from oldest on the left and more recent on the right. This is unintuitive as = is a comparative operator in sql and works for both "EmployeeId = 1" or "1 = EmployeeId" in t...
How to push different local Git branches to Heroku/master
..., you can push without using the -f, the -f (force flag) is recommended in order to avoid conflicts with other developers’ pushes.
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What is an idempotent operation?
... information, you can PUT the new information as many times as it takes in order to get confirmation from the web service. PUT-ing it a thousand times is the same as PUT-ing it once. Similarly DELETE-ing a REST resource a thousand times is the same as deleting it once. Idempotence thus makes it a...
Android: How to handle right to left swipe gestures
...e scroll view get disabled and therefore scroll action does not happen. In order to fix this you need to override the dispatchTouchEvent method of the Activity and return the inherited version of this method after you're done with your own listener.
In order to do a few modifications to Mirek's cod...
Plotting time in Python with Matplotlib
...erstand why this is the 5th question I've encountered where no one has actually TRIED using a scatter plot - it doesn't work. Type Error - invalid type promotion.
– dwanderson
Oct 5 '16 at 16:21
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Why Doesn't C# Allow Static Methods to Implement an Interface?
...int id) { ... }
void SomeOtherMethod()
{
//do work...
}
}
in order to use instantination for solving the static interface problem we need to do the following thing:
public class Customer: IDoSomeStaticMath
{
//create new customer
public Customer(Transaction t) { ... }
//open exi...
How to find out what group a given user has?
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This one shows the user's uid as well as all the groups (with their gids) they belong to
id userid
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How do I delete rows in a data frame?
...ld generally avoid deleting rows by numeric position. This is because the order of the rows in your data may change in the future. A general principle of a data.frame or database tables is that the order of the rows should not matter. If the order does matter, this should be encoded in an actual va...