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How to make a variadic macro (variable number of arguments)
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The reason for ## before VA_ARGS is that it swallows the preceding comma in case the variable-argument list is empty, eg. FOO("a") expands to printf("a"). This is an extension of gcc (and vc++, maybe), C99 requires at least one argument to be present in place of the elli...
Correct way to define Python source code encoding
...f you want to be 100% python-docs-recommendation-compatible.
More specifically, you need to use whatever is recognized by Python and the specific editing software you use (if it needs/accepts anything at all). E.g. the coding form is recognized (out of the box) by GNU Emacs but not Vim (yes, withou...
When to use symbols instead of strings in Ruby?
...iers. For Ruby < 2.2 only use symbols when they aren't generated dynamically, to avoid memory leaks.
Full answer
The only reason not to use them for identifiers that are generated dynamically is because of memory concerns.
This question is very common because many programming languages don't h...
Replace all non-alphanumeric characters in a string
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If you handle unicode a lot, you may also need to keep all non-ASCII unicode symbols: re.sub("[\x00-\x2F\x3A-\x40\x5B-\x60\x7B-\x7F]+", " ", ":%# unicode ΣΘΙП@./\n")
– zhazha
Jul 13 '16 at 7:43
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Broadcast receiver for checking internet connection in android app
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Answer to your first question: Your broadcast receiver is being called two times because
You have added two <intent-filter>
Change in network connection :
<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
Change in WiFi state:
<action android:name="android....
Specify an SSH key for git push for a given domain
...ult key is) will take precedence over the one you pass in via -i. So you really want to use GIT_SSH_COMMAND='ssh -i ~/.ssh/your_private_key -o IdentitiesOnly=yes' to make it ignore other keys
– staktrace
Jan 9 '19 at 19:05
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Python: fastest way to create a list of n lists
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The probably only way which is marginally faster than
d = [[] for x in xrange(n)]
is
from itertools import repeat
d = [[] for i in repeat(None, n)]
It does not have to create a new int object in every iteration and is about 15 % faster on my machine.
Edi...
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 can I alter a primary key constraint using SQL syntax?
...y constraint name, use query found here to look it up (or look up and drop all at once). http://stackoverflow.com/a/13948609/945875
– Justin
Dec 19 '13 at 20:06
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How to properly add cross-site request forgery (CSRF) token using PHP
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