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Why create “Implicitly Unwrapped Optionals”, since that implies you know there's a value?
... var button: UIButton!
var buttonOriginalWidth: CGFloat!
override func awakeFromNib() {
self.buttonOriginalWidth = self.button.frame.size.width
}
}
Here, you cannot calculate the original width of the button until the view loads, but you know that awakeFromNib will be called b...
How do I replace NA values with zeros in an R dataframe?
...ce(., is.na(.), 0))
The Complete Analysis -
Updated for dplyr 0.8.0: functions use purrr format ~ symbols: replacing deprecated funs() arguments.
Approaches tested:
# Base R:
baseR.sbst.rssgn <- function(x) { x[is.na(x)] <- 0; x }
baseR.replace <- function(x) { replace(x, is...
How is Math.Pow() implemented in .NET Framework?
... things up, I decided to take a look at the implementation of Math.Pow() function. But in .NET Reflector , all I found was this:
...
Haskell: Lists, Arrays, Vectors, Sequences
... standard library, and for that matter the prelude, is full of useful list functions that should litter your code (foldr,map,filter). Lists are persistant , aka purely functional, which is very nice. Haskell lists aren't really "lists" because they are coinductive (other languages call these strea...
Templated check for the existence of a class member function?
...to write a template that changes behavior depending on if a certain member function is defined on a class?
29 Answers
...
Pointer expressions: *ptr++, *++ptr and ++*ptr
...hen increments dereferenced value
And here's a fourth, every bit as much fun as the other three:
(*ptr)++ // effectively forces a dereference, then increments dereferenced value
The first and second will crash if ptr is actually an array identifier. The third and fourth will crash if ptr points...
How Drupal works? [closed]
...can be confusing on this front, partially because it has a relatively deep function stack. Although it's procedural PHP it's purely event/listener driven in its architecture, and there's no simple "flow" in the main PHP script for you to look though. I recently did a presentation on this very subjec...
How to trace the path in a Breadth-First Search?
...
I thought I'd try code this up for fun:
graph = {
'1': ['2', '3', '4'],
'2': ['5', '6'],
'5': ['9', '10'],
'4': ['7', '8'],
'7': ['11', '12']
}
def bfs(graph, forefront, end):
# assumes no cycles
next_...
When does invoking a member function on a null instance result in undefined behavior?
...ult in undefined behavior. It's always undefined behavior to call a member function through a null pointer. If the function is static, it's technically undefined as well, but there's some dispute.
The first thing to understand is why it's undefined behavior to dereference a null pointer. In C++03...
How can I profile C++ code running on Linux?
...ot precision of measure. So for example, there can be, mid-stack, a single function call A(); that accounts for 50% of time, but it can be in another large function B, along with many other calls to A() that are not costly. Precise summaries of function times can be a clue, but every other stack sam...