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How to determine the Boost version on a system?
... You can quickly look up the current value via e.g. echo -e '#include <boost/version.hpp>\nBOOST_VERSION' | gcc -x c++ -E - - for example on Fedora 26: 106300 (i.e. 1.63)
– maxschlepzig
Jul 22 '17 at 14:07
...
How to randomize (or permute) a dataframe rowwise and columnwise?
...df1
a b c
1 1 1 0
2 1 0 0
3 0 1 0
4 0 0 0
Shuffle row-wise:
> df2 <- df1[sample(nrow(df1)),]
> df2
a b c
3 0 1 0
4 0 0 0
2 1 0 0
1 1 1 0
By default sample() randomly reorders the elements passed as the first argument. This means that the default size is the size of the passed arra...
Unix command to prepend text to a file
...
Process Substitution
I'm surprised no one mentioned this.
cat <(echo "before") text.txt > newfile.txt
which is arguably more natural than the accepted answer (printing something and piping it into a substitution command is lexicographically counter-intuitive).
...and hijacking ...
Can constructors be async?
...get” void, or Task.
If the constructor of type T actually returned Task<T>, that would be very confusing, I think.
If the async constructor behaved the same way as an async void method, that kind of breaks what constructor is meant to be. After constructor returns, you should get a fully i...
EF Code First “Invalid column name 'Discriminator'” but no inheritance
...nore a type that is not mapped to a database table
modelBuilder.Ignore<PersonViewModel>();
// ignore a property that is not mapped to a database column
modelBuilder.Entity<Person>()
.Ignore(p => p.FullName);
}
...
Allow user to select camera or gallery for image
... have to create your own chooser dialog merging both intent resolution results.
To do this, you will need to query the PackageManager with PackageManager.queryIntentActivities() for both original intents and create the final list of possible Intents with one new Intent for each retrieved activity l...
.NET WPF Remember window size between sessions
... be needed.
Initialise the first two to 0 and the second two to the default size of your application, and the last one to false.
Create a Window_OnSourceInitialized event handler and add the following:
this.Top = Properties.Settings.Default.Top;
this.Left = Properties.Settings.Default.Left;
this...
Can't operator == be applied to generic types in C#?
...
"...by default == behaves as described above for both predefined and user-defined reference types."
Type T is not necessarily a reference type, so the compiler can't make that assumption.
However, this will compile because it is more e...
How to navigate through a vector using iterators? (C++)
...e first and the last element respectively.
using namespace std;
vector<string> myvector; // a vector of stings.
// push some strings in the vector.
myvector.push_back("a");
myvector.push_back("b");
myvector.push_back("c");
myvector.push_back("d");
vector<string>::iterator it; /...
Pass mouse events through absolutely-positioned element
...my version here: gist.github.com/Pichan/5498404
– jpeltoniemi
May 1 '13 at 21:12
2
The problem wi...