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Converting a List to a comma separated string
Is there a way to take a List and convert it into a comma separated string?
8 Answers
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How to check if a variable is set in Bash?
...ar+x} is a parameter expansion which evaluates to nothing if var is unset, and substitutes the string x otherwise.
Quotes Digression
Quotes can be omitted (so we can say ${var+x} instead of "${var+x}") because this syntax & usage guarantees this will only expand to something that does not requ...
How do I create a new class in IntelliJ without using the mouse?
...near the existing one or use arrow keys to navigate through the packages.
And yet another way is to just type the class name in the existing code where you want to use it, IDEA will highlight it in red as it doesn't exist yet, then press Alt+Enter for the Intention Actions pop-up, choose Create Cla...
LINQ where vs takewhile
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TakeWhile stops when the condition is false, Where continues and find all elements matching the condition
var intList = new int[] { 1, 2, 3, 4, 5, -1, -2 };
Console.WriteLine("Where");
foreach (var i in intList.Where(x => x <= 3))
Console.WriteLine(i);
Console.WriteLine("Take...
Counting occurrences in Vim without marking the buffer changed
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To avoid the substitution, leave the second pattern empty, and add the “n” flag:
:%s/pattern-here//gn
This is described as an official tip.
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How to declare array of zeros in python (or an array of a certain size) [duplicate]
...histogram of counts... so I create buckets.
I know I could just go through and append a bunch of zeros i.e something along these lines:
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Decorators with parameters?
...ecorator with arguments should return a function that will take a function and return another function. So it should really return a normal decorator. A bit confusing, right? What I mean is:
def decorator_factory(argument):
def decorator(function):
def wrapper(*args, **kwargs):
...
How to get indices of a sorted array in Python
... 2), (2, 3), (3, 100), (4, 5)]
You sort the list by passing it to sorted and specifying a function to extract the sort key (the second element of each tuple; that's what the lambda is for. Finally, the original index of each sorted element is extracted using the [i[0] for i in ...] list comprehens...
ANTLR: Is there a simple example?
...ing the examples at the antlr.org site, I still can't get a clear understanding of the grammar to Java process.
5 Answers...
Ball to Ball Collision - Detection and Handling
...y mass, the new velocities can be calculated using the equations (where v1 and v2 are the velocities after the collision, and u1, u2 are from before):
If the balls have the same mass then the velocities are simply switched. Here's some code I wrote which does something similar:
void Simulati...