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Group by multiple columns in dplyr, using string vector input
I'm trying to transfer my understanding of plyr into dplyr, but I can't figure out how to group by multiple columns.
9 Answ...
What does the constant 0.0039215689 represent?
...was the multiply-by-reciprocal optimization. So I checked in my calculator and sure enough - I guessed right.
– Mysticial
Mar 24 '14 at 22:08
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WPF datagrid empty row at bottom
...e to explicitly add that line of code to hide the additional row (or check and uncheck the check box)
– Tobias Valinski
Nov 28 '13 at 10:39
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What is the purpose of a plus symbol before a variable?
...icating the if on whether or not d is a non-zero number.
Reference here. And, as pointed out in comments, here.
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How would you compare jQuery objects?
...etty much nothing is required other than ensuring they are the same length and share identical nodes. Here is a small code snippet. You may even want to convert this into a jquery plugin for your own uses.
jQuery(function($) {
// Two separate jQuery references
var divs = $("div");
var divs2...
What is
I'm having trouble understanding the following syntax:
5 Answers
5
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Add data annotations to a class generated by entity framework
... all situations, In the first case you can describe field validation rules and in the second case try to describe purposes
– dimonser
Mar 31 '15 at 14:14
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iPhone OS: How do I create an NSDate for a specific date?
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@Chuck's answer is correct, and lead me to the following code. Thought I'd share:
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:10];
[comps setMonth:10];
[comps setYear:2010];
NSDate *date = [[NSCalendar currentCalendar] date...
UICollectionView current visible cell index
...e in my iPad application.
I have set UICollectionView such that its size and cell size is same, means only once cell is displayed at a time.
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Checking user's homepage in Internet Explorer
...he same domain. For example, if www.microsoft.com is set as your homepage, and you call this method from a page on the Microsoft® Web site, then the isHomePage method returns true. However, if your homepage is set to www.microsoft.com and you call this method from a page on a different domain, the ...