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How can I profile C++ code running on Linux?
... stack. If there is some code that is wasting some percentage of the time, 20% or 50% or whatever, that is the probability that you will catch it in the act on each sample. So, that is roughly the percentage of samples on which you will see it. There is no educated guesswork required. If you do have...
Why can't R's ifelse statements return vectors?
...st vectors, you will get longer results:
> ifelse(c(TRUE, FALSE), c(1, 2), c(3, 4))
[1] 1 4
So ifelse is intended for the specific purpose of testing a vector of booleans and returning a vector of the same length, filled with elements taken from the (vector) yes and no arguments.
It is a comm...
javascript i++ vs ++i [duplicate]
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207
The difference between i++ and ++i is the value of the expression.
The value i++ is the value...
Numpy first occurrence of value greater than existing value
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207
This is a little faster (and looks nicer)
np.argmax(aa>5)
Since argmax will stop at the ...
Sort hash by key, return hash in Ruby
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229
In Ruby 2.1 it is simple:
h.sort.to_h
...
HSL to RGB color conversion
...m, but is archived here and the original author has a gist - thanks to user2441511).
The code is re-posted below:
HSL to RGB:
/**
* Converts an HSL color value to RGB. Conversion formula
* adapted from http://en.wikipedia.org/wiki/HSL_color_space.
* Assumes h, s, and l are contained in the se...
Printing the correct number of decimal points with cout
I have a list of float values and I want to print them with cout with 2 decimal places.
12 Answers
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How to iterate a loop with index and element in Swift
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print("Item \(index): \(element)")
}
Before Swift 3.0 and after Swift 2.0, the function was called enumerate():
for (index, element) in list.enumerate() {
print("Item \(index): \(element)")
}
Prior to Swift 2.0, enumerate was a global function.
for (index, element) in enumerate(list) {
...
How to find the sum of an array of numbers
Given an array [1, 2, 3, 4] , how can I find the sum of its elements? (In this case, the sum would be 10 .)
43 Answers
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Understanding how recursive functions work
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2
I'm not too happy with thinking of it as a copy. I find that a more intuitive explanation is to differentiate the function itself (the code,...