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Where does R store packages?
...all.packages() function in R is the automatic unzipping utility that gets and install packages in R.
4 Answers
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How do I conditionally apply CSS styles in AngularJS?
...ange dynamically. Think programmable control of the style values.
ng-show and ng-hide - use if you only need to show or hide something (modifies CSS)
ng-if - new in version 1.1.5, use instead of the more verbose ng-switch if you only need to check for a single condition (modifies DOM)
ng-switch - u...
Is it possible to read from a InputStream with a timeout?
...tream always returns 0.
This method should be overridden by subclasses.
And indeed, the concrete input stream classes do override available(), providing meaningful values, not constant 0s.
Second Caveat: Ensure you use carriage-return when typing input in Windows.
If using System.in, your progr...
Can media queries resize based on a div element instead of the screen?
...he screen size as the div is just used like a widget within the webpage, and its size can vary.
11 Answers
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Abort makefile if variable not set
...ning an auxiliary function for that:
# Check that given variables are set and all have non-empty values,
# die with an error otherwise.
#
# Params:
# 1. Variable name(s) to test.
# 2. (optional) Error message to print.
check_defined = \
$(strip $(foreach 1,$1, \
$(call __check_defin...
What does “atomic” mean in programming?
... written using two separate operations: one that writes the first 32 bits, and a second one which writes the last 32 bits. That means that another thread might read the value of foo, and see the intermediate state.
Making the operation atomic consists in using synchronization mechanisms in order t...
Should an Enum start with a 0 or a 1?
...ag enum values of zero unless the value represents "all flags are cleared" and is named appropriately, as prescribed by the next guideline.
✔️ DO name the zero value of flag enums None. For a flag enum, the value must always mean "all flags are cleared."
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“You have mail” message in terminal, os X [closed]
...ably it is some message from your system.
Type in terminal:
man mail
, and see how can you get this message from your system.
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Python unittest - opposite of assertRaises?
...r test must exit with a failure condition, not an error one. On the other hand, if in running the same code you would raise a KeyError, that would be an error, not a failure. In python - differently than some other languages - Exceptions are routinely used for control flow, this is why we have the e...
Can I start the iPhone simulator without “Build and Run”?
I want to delete an app in the simulator before I "build and run". How can I start the simulator so I can do the deletion? If I start it by "build and run" I get a long log output that takes a while because of a bug I'm trying to fix. I'd like to avoid that.
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