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What does !! mean in ruby?
...ly not necessary to use though since the only false values to Ruby are nil and false, so it's usually best to let that convention stand.
Think of it as
!(!some_val)
One thing that is it used for legitimately is preventing a huge chunk of data from being returned. For example you probably don't ...
What does 'predicate' mean in the context of computer science? [duplicate]
...ies a boolean function, i.e. a predicate.
– Dimitris Andreou
Jul 24 '10 at 17:25
7
This is used i...
Can I simultaneously declare and assign a variable in VBA?
I'm new to VBA and want to know if I can convert the following declaration and assignment into one line:
5 Answers
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Are there disadvantages to using a generic varchar(255) for all text-based fields?
...se Ruby on Rails migrations map String fields to VARCHAR(255) by default and I never bothered to override it).
7 Answer...
How do I properly compare strings in C?
...trying to get a program to let a user enter a word or character, store it, and then print it until the user types it again, exiting the program. My code looks like this:
...
Bootstrap: How do I identify the Bootstrap version?
... License v2.0
* http://www.apache.org/licenses/LICENSE-2.0
*
* Designed and built with all the love in the world @twitter by @mdo and @fat.
*/
If they are not there, then they have probably been deleted.
VERSIONS:
You can review version history here. Backward compatibility shouldn't be broke...
addEventListener vs onclick
What's the difference between addEventListener and onclick ?
16 Answers
16
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Are global variables in PHP considered bad practice? If so, why?
...l way. I generally have a variable that contains the system configuration, and when I nead to access this variable in a function, I do global $var; .
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Why switch is faster than if
...ave a check, a jump to the next clause, a check, a jump to the next clause and so on. With switch the JVM loads the value to compare and iterates through the value table to find a match, which is faster in most cases.
share
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How do I delete rows in a data frame?
...
The key idea is you form a set of the rows you want to remove, and keep the complement of that set.
In R, the complement of a set is given by the '-' operator.
So, assuming the data.frame is called myData:
myData[-c(2, 4, 6), ] # notice the -
Of course, don't forget to "reassign" ...