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Sample random rows in dataframe
...le_n:
sample_n(df, 10)
randomly samples 10 rows from the dataframe. It calls sample.int, so really is the same answer with less typing (and simplifies use in the context of magrittr since the dataframe is the first argument).
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How to sort a dataframe by multiple column(s)
... as speedy as the base R commands with their convoluted machinations. Typically brilliant Hadley Wickham work. My only gripe with it is that it breaks the standard R nomenclature where sorting objects get called by sort(object), but I understand why Hadley did it that way due to issues discussed i...
What is the difference between const and readonly in C#?
... time of a definition for a const VS readonly values can be computed dynamically but need to be assigned before the constructor exits.. after that it is frozen.
'const's are implicitly static. You use a ClassName.ConstantName notation to access them.
There is a subtle difference. Consider a class ...
Java: Difference between PrintStream and PrintWriter
... file on one platform and consuming it on another.
With a Writer, you typically specify the encoding to use, avoiding any platform dependencies.
Why bother having a PrintStream in the JDK, since the primary intent is to write characters, and not bytes? PrintStream predates JDK 1.1 when Reader/Writ...
Detecting when user scrolls to bottom of div with jQuery
I have a div box (called flux) with a variable amount of content inside.
This divbox has overflow set to auto.
14 Answers
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What's the best way of scraping data from a website? [closed]
... programming interface or another mechanism to access that data programmatically.
2 Answers
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C/C++ line number
...intln(a, args...) print(a "\n", ##args)
These macros should behave identically to printf(), while including java stacktrace-like information. Here's an example main:
void exampleMethod() {
println("printf() syntax: string = %s, int = %d", "foobar", 42);
}
int main(int argc, char** argv) {
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AngularJS For Loop with Numbers & Ranges
... You have to watch out for things like this. The range function will get called multiple times for each item in the list. You can get nasty memory leaks and you're generating a lot of function calls. It almost seems easier to put the collection inside the controller.
– Lucas...
Google Maps API v3: Can I setZoom after fitBounds?
...p "skip". Instead listen for the "zoom_change" event, and set it up before calling fitBounds(). See my answer below
– Benjamin Sussman
Dec 12 '12 at 16:17
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Useful code which uses reduce()? [closed]
...ge(1,1000))', number=1000) takes 0.36 seconds (about 4 times slower). Basically multiplication by 10 becomes expensive when the list gets big, while int to str and concatenation stays cheap.
– dr jimbob
Aug 21 '13 at 17:18
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