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How to convert a data frame column to numeric type?
... 3
4 d 4 4 d 4
5 e 5 5 e 5
and let us run:
> sapply(d, mode)
char fake_char fac char_fac num
"character" "character" "numeric" "numeric" "numeric"
> sapply(d, class)
char fake_char fac char...
How to turn on line numbers in IDLE?
...on 3.8 or newer:
To show line numbers in the current window, go to Options and click Show Line Numbers.
To show them automatically, go to Options > Configure IDLE > General and check the Show line numbers in new windows box.
Version 3.7 or older:
Unfortunately there is not an option to display...
Aspect Oriented Programming vs. Object-Oriented Programming
Like most developers here and in the entire world, I have been developing software systems using object-oriented programming (OOP) techniques for many years. So when I read that aspect-oriented programming (AOP) addresses many of the problems that traditional OOP doesn't solve completely or directly...
What does an underscore in front of an import statement mean?
...river{})
Once it's registered in this way, sqlite3 can be used with the standard library's sql interface in your code like in the example:
db, err := sql.Open("sqlite3", "./foo.db")
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How can I make git show a list of the files that are being tracked?
Using command line git, how can I make git show a list of the files that are being tracked in the repository?
4 Answers
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How is CountDownLatch used in Java Multithreading?
Can someone help me to understand what Java CountDownLatch is and when to use it?
12 Answers
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How to hide TabPage from TabControl [duplicate]
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No, this doesn't exist. You have to remove the tab and re-add it when you want it. Or use a different (3rd-party) tab control.
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SQL order string as number
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and if you have mixed string and number and want them both sorted, use "order by col * 1, col"
– Hayden Thring
Feb 23 '15 at 3:42
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Disable copy constructor
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You can make the copy constructor private and provide no implementation:
private:
SymbolIndexer(const SymbolIndexer&);
Or in C++11, explicitly forbid it:
SymbolIndexer(const SymbolIndexer&) = delete;
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switch() statement usage
...ue again. It seems switch is generally faster than if statements.
So that, and the fact that the code is shorter/neater with a switch statement leans in favor of switch:
# Simplified to only measure the overhead of switch vs if
test1 <- function(type) {
switch(type,
mean = 1,
m...