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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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javascript check for not null
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while technically this works, a double not (!!) is a programming faux-pas. It is really the equivalent of if(val), which is much clearer to read. I would stick to that (fyi Ujwal, !!val should technically work in C or C++ also) see here f...
What is the purpose of Order By 1 in SQL select statement?
...is only has the sql tag. In Standard SQL only column correlation names are allowed in the OREDER BY clause because, in theory, the table correlation names are out of scope i.e. should be ORDER BY PAYMENT_DATE;. Of course, not all SQL implementations conform to Standards.
– oned...
Page redirect after certain time PHP
...ect you to wherever.php in 5 seconds
Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP. It is a very common error to read code with include, or require, functions, or another file access function, and have spa...
Persist javascript variables across pages? [duplicate]
...mp; sessionStorage of HTML5. These are supported in the latest versions of all modern browsers, and are much easier to use and less fiddly than cookies.
http://www.w3.org/TR/2009/WD-webstorage-20091222/
https://www.w3.org/TR/webstorage/. (second edition)
Here are some sample code for setting and ...
Double decimal formatting in Java
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Optionally u might want to add another separator for digits more than 3 before the comma then use the following NumberFormat formatter = new DecimalFormat("#,000.00"); System.out.println(formatter.format(4.0));
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How can I confirm a database is Oracle & what version it is using SQL?
I'm building an installer for an application. The user gets to select a datasource they have configured and nominate what type of database it is. I want to confirm that the database type is indeed Oracle, and if possible, what version of Oracle they are running by sending a SQL statement to the dat...
Embed image in a element
...shown but for some reason not in the center - so it's impossible to see it all.
In other words it seems like the top right corner of the image is located at the center of the button and not at the top right corner of the button.
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How to run Selenium WebDriver test cases in Chrome?
... need to download the executable driver from:
ChromeDriver Download
Then all you need to do is use the following before creating the driver object (already shown in the correct order):
System.setProperty("webdriver.chrome.driver", "/path/to/chromedriver");
WebDriver driver = new ChromeDriver();
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How can I explode and trim whitespace?
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This is also looping (internally) by PHP
– Jason OOO
Oct 13 '13 at 15:47
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