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How to select the rows with maximum values in each group with dplyr? [duplicate]
...icated maximum values present. Otherwise, the filter approach would return all maximum values (rows) per group while the OP's ddply approach with which.max would only return one maximum (the first) per group. To replicate that behavior, another option is to use slice(which.max(value)) in dplyr.
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The model backing the context has changed since the database was created
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Ps, this goes in Global.asax Application_Start()
– BritishDeveloper
Feb 23 '13 at 0:08
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How to uninstall editable packages with pip (installed with -e)
I have installed some packages with -e
6 Answers
6
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Why '&&' and not '&'?
...luation of the rest (op.CanExecute()) is skipped.
Apart from this, technically, they are different, too:
&& and || can only be used on bool whereas & and | can be used on any integral type (bool, int, long, sbyte, ...), because they are bitwise operators. & is the bitwise AND operat...
How to get the anchor from the URL using jQuery?
...xOf() and .substring(), like this:
var url = "www.aaa.com/task1/1.3.html#a_1";
var hash = url.substring(url.indexOf("#")+1);
You can give it a try here, if it may not have a # in it, do an if(url.indexOf("#") != -1) check like this:
var url = "www.aaa.com/task1/1.3.html#a_1", idx = url.indexOf("...
Get a pixel from HTML Canvas?
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There's a section about pixel manipulation in the W3C documentation.
Here's an example on how to invert an image:
var context = document.getElementById('myCanvas').getContext('2d');
// Get the CanvasPixelArray from the given coordinates and dimensi...
Using headers with the Python requests library's get method
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According to the api, the headers can all be passed in using requests.get:
r=requests.get("http://www.example.com/", headers={"content-type":"text"})
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What is the difference between IEqualityComparer and IEquatable?
...ted) IEqualityComparer<T> is an interface for an object (which is usually a lightweight class different from T) that provides comparison functions that operates on T
– rwong
Feb 22 at 16:40
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PHP - iterate on string characters
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Just note that you're calling strlen() on each iteration. Not a terrible thing, since PHP has the length precalculated, but still a function call. If you have a need for speed, better save that in a variable before starting the loop.
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Copy all files and folders using msbuild
...sbuild scripts that I am trying to write. What I would like to do is copy all the files and sub folders from a folder to another folder using msbuild.
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