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What does T&& (double ampersand) mean in C++11?
...e in the draft C++11 standard, but are not true for the final one! Specifically, it says at various points that rvalue references can bind to lvalues, which was once true, but was changed.(e.g. int x; int &&rrx = x; no longer compiles in GCC) – drewbarbs Jul 13 '14 at 16:12
The biggest d...
How can I do a line break (line continuation) in Python?
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Actually, you have the style guide's preference exactly backwards. Implicit continuation is preferred, explicit backslash is to be used only if necessary.
– Carl Meyer
Sep 11 '08 at 19:00
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Summarizing multiple columns with dplyr? [duplicate]
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The dplyr package contains summarise_all for this aim:
library(dplyr)
df %>% group_by(grp) %>% summarise_all(list(mean))
#> # A tibble: 3 x 5
#> grp a b c d
#> <int> <dbl> <dbl> <dbl> <dbl>
#>...
What is the difference between “ is None ” and “ ==None ”
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class Foo:
def __eq__(self,other):
return True
foo=Foo()
print(foo==None)
# True
print(foo is None)
# False
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Passing variable arguments to another function that accepts a variable argument list
...gs)
{
...whatever you planned to have exampleB do...
...except it calls neither va_start nor va_end...
}
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What's the state of the art in email validation for Rails?
... answered Aug 24 '10 at 9:56
HallelujahHallelujah
77466 silver badges44 bronze badges
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Split files using tar, gz, zip, or bzip2 [closed]
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Actually using -b 1024MiB gave an error that it was an invalid number of bytes. Using --bytes=1024m works.
– Brian
Mar 13 '14 at 12:52
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How can I start an interactive console for Perl?
...ms to provide the best almost-out-of-the-box solution (you may have to install rlwrap). All third-party REPL/console solutions, including perlconsole, are cumbersome to install and often have more limitations.
– mklement0
Jul 8 '15 at 3:09
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Bold & Non-Bold Text In A Single UILabel?
...deal with iOS5 old stuff besides syntax is shorter so everything becomes really simple:
Swift 5
func attributedString(from string: String, nonBoldRange: NSRange?) -> NSAttributedString {
let fontSize = UIFont.systemFontSize
let attrs = [
NSAttributedString.Key.font: UIFont.bold...
What is a NullPointerException, and how do I fix it?
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When you declare a reference variable (i.e. an object) you are really creating a pointer to an object. Consider the following code where you declare a variable of primitive type int:
int x;
x = 10;
In this example, the variable x is an int and Java will initialize it to 0 for you. When yo...