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Mean per group in a data.frame [duplicate]
I have a data.frame and I need to calculate the mean per group (i.e. per Month , below).
8 Answers
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Match linebreaks - \n or \r\n?
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Gonna answer in opposite direction.
2) For a full explanation about \r and \n I have to refer to this question, which is far more complete than I will post here: Difference between \n and \r?
Long story short, Linux uses \n for a new-line, Windows \r\n and old Macs \r. So there are multiple way...
When is it better to use an NSSet over an NSArray?
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In your example, you are adding primitives to an array and a set. Neither is possible because they can only contain objects.
– FreeAsInBeer
Jun 12 '12 at 13:28
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Regular expression to allow spaces between words
I want a regular expression that prevents symbols and only allows letters and numbers. The regex below works great, but it doesn't allow for spaces between words.
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Maven Could not resolve dependencies, artifacts could not be resolved
...project from my friend. He demonstrated the project right in front of me, and then I copied the project, imported it as an existing maven project (I'm using m2eclipse plugin).
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How do I set up DNS for an apex domain (no www) pointing to a Heroku app?
I already added a custom domain to my Heroku app and it works with www.domain.com .
4 Answers
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Reading a huge .csv file
...ying to read data from .csv files in Python 2.7 with up to 1 million rows, and 200 columns (files range from 100mb to 1.6gb). I can do this (very slowly) for the files with under 300,000 rows, but once I go above that I get memory errors. My code looks like this:
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Python string prints as [u'String']
...duces Unicode. So you need to convert the list to a single unicode string, and then convert that to ASCII.
I don't know exaxtly how you got the one-element lists; the contents member would be a list of strings and tags, which is apparently not what you have. Assuming that you really always get a li...
Remove header and footer from window.print()
I am using window.print() for printing page, but I got header and footer contains page title, file path, page number and date. How to remove them?
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Casperjs/PhantomJs vs Selenium
... have seen majority of our users using Chrome. So we wanted to know - pros and cons of using PhantomJS vs Selenium:
5 Answe...