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Null coalescing in powershell
... evaluated
Null Conditional Assignment
$x = $null
$x ??= 100 # $x is now 100
$x ??= 200 # $x remains 100
Ternary Operator
$true ? "this value returned" : "this expression not evaluated"
$false ? "this expression not evaluated" : "this value returned"
Previous Versions:
No need for ...
Simple explanation of MapReduce?
...rite it like this
A = [7, 8, 9]
sum = A.reduce( 0, (x, y) => x + y )
Now it's a little confusing why there are 2 arguments (0 and the function with x and y) passed. For a reduce function to be useful, it must be able to take 2 items, compute something and "reduce" that 2 items to just one sing...
How do I download a package from apt-get without installing it? [closed]
...d <package_name> (similar to biocyberman's answer but I think apt is now more common than aptitude).
– Dan R
Aug 22 '17 at 5:28
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Android: upgrading DB version and adding new table
I've already created sqlite tables for my app, but now I want to add a new table to the database.
5 Answers
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When to use virtual destructors?
...Here, you'll notice that I didn't declare Base's destructor to be virtual. Now, let's have a look at the following snippet:
Base *b = new Derived();
// use b
delete b; // Here's the problem!
Since Base's destructor is not virtual and b is a Base* pointing to a Derived object, delete b has undefin...
How to change Git log date formats
... (either committer’s or author’s).
There is no built-in way that I know of to create a custom format, but you can do some shell magic.
timestamp=`git log -n1 --format="%at"`
my_date=`perl -e "print scalar localtime ($timestamp)"`
git log -n1 --pretty=format:"Blah-blah $my_date"
The first s...
ModelState.IsValid == false, why?
...eturn Values.All(modelState => modelState.Errors.Count == 0);
}
}
Now, it looks like it can't be. Well, that's for ASP.NET MVC v1.
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numpy: most efficient frequency counts for unique values in an array
...y 1.9, the easiest and fastest method is to simply use numpy.unique, which now has a return_counts keyword argument:
import numpy as np
x = np.array([1,1,1,2,2,2,5,25,1,1])
unique, counts = np.unique(x, return_counts=True)
print np.asarray((unique, counts)).T
Which gives:
[[ 1 5]
[ 2 3]
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Where is Xcode's build folder?
...
~/Library/Developer/Xcode/DerivedData is now the default.
You can set the prefs in Xcode to allow projects to specify their build directories.
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What data type to use for hashed password field and what length?
... works (will be implementing it later), but need to create database schema now.
10 Answers
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