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Object reference not set to an instance of an object.Why doesn't .NET show which object is `null`?
...ull
IL_0002: stloc.0 // s
IL_0003: ldloc.0 // s
IL_0004: callvirt System.String.get_Length
IL_0009: call System.Console.WriteLine
It is the callvirt opcode that throws the NullReferenceException and it does that when the first argument on the evaluation stack is a null ...
Is inject the same thing as reduce in ruby?
... If you want to create your own aliases, you may be interested in alias_method.
– Nick McCurdy
Oct 25 '13 at 2:16
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Rails raw SQL example
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and then you'd need to call values on this PG::Result object to get the results array
– jobwat
Mar 26 '14 at 1:00
3
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How do I check if a string is a number (float)?
...r.
I'm not sure that anything much could be faster than the above. It calls the function and returns. Try/Catch doesn't introduce much overhead because the most common exception is caught without an extensive search of stack frames.
The issue is that any numeric conversion function has two kin...
What Automatic Resource Management alternatives exist for Scala?
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For now Scala 2.13 has finally supported: try with resources by using Using :), Example:
val lines: Try[Seq[String]] =
Using(new BufferedReader(new FileReader("file.txt"))) { reader =>
Iterator.unfold(())(_ => Option(reader.readLine()).ma...
How to base64 encode image in linux bash / shell
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You need to use cat to get the contents of the file named 'DSC_0251.JPG', rather than the filename itself.
test="$(cat DSC_0251.JPG | base64)"
However, base64 can read from the file itself:
test=$( base64 DSC_0251.JPG )
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How to convert list of tuples to multiple lists?
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xs, ys = [x for x, y in zs], [y for x, y in zs]
return xs, ys
if __name__ == '__main__':
from timeit import timeit
setup_string='''\
N = 2000000
xs = list(range(1, N))
ys = list(range(N+1, N*2))
zs = list(zip(xs, ys))
from __main__ import t1, t2, t3
'''
print(f'zip:\t\t{timeit(...
How to make a Java Generic method static?
...urn value always introduce (declare) a new generic type variable.
Additionally, type variables between types (ArrayUtils) and static methods (appendToArray) never interfere with each other.
So, what does this mean:
In my answer <E> would hide the E from ArrayUtils<E> if the method woul...
How to remove non-alphanumeric characters?
I need to remove all characters from a string which aren't in a-z A-Z 0-9 set or are not spaces.
9 Answers
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How to extract a git subdirectory and make a submodule out of it?
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Nowadays there's a much easier way to do it than manually using git filter-branch: git subtree
Installation
NOTE git-subtree is now part of git (if you install contrib) as of 1.7.11, so you might already have it installed. You may check by executing git subtree.
To install...