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How does the HyperLogLog algorithm work?
I've been learning about different algorithms in my spare time recently, and one that I came across which appears to be very interesting is called the HyperLogLog algorithm - which estimates how many unique items are in a list.
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Apply a function to every row of a matrix or a data frame
Suppose I have a n by 2 matrix and a function that takes a 2-vector as one of its arguments. I would like to apply the function to each row of the matrix and get a n-vector. How to do this in R?
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How do I format a Microsoft JSON date?
...t(jsonDate.substr(6)));
The substr() function takes out the /Date( part, and the parseInt() function gets the integer and ignores the )/ at the end. The resulting number is passed into the Date constructor.
I have intentionally left out the radix (the 2nd argument to parseInt); see my comment b...
iPhone Safari Web App opens links in new window
...is launched from Home Screen, all links will open in new window in Safari (and lose full screen functionality). How can I prevent it? I couldn't find any help, only the same unanswered question.
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Benefits of using the conditional ?: (ternary) operator
What are the benefits and drawbacks of the ?: operator as opposed to the standard if-else statement. The obvious ones being:
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How to redirect and append both stdout and stderr to a file with Bash?
...left to right as follows:
>>file.txt: Open file.txt in append mode and redirect stdout there.
2>&1: Redirect stderr to "where stdout is currently going". In this case, that is a file opened in append mode. In other words, the &1 reuses the file descriptor which stdout currently us...
How can I merge two commits into one if I already started rebase?
...base todo list, that is into a commit on a previous line. Changing the command on your todo list’s very first line to squash will always produce this error as there is nothing for the first commit to squash into.
The Fix
First get back to where you started with
$ git rebase --abort
Say your h...
How to import multiple .csv files at once?
...you have those CSVs in a single directory--your current working directory--and that all of them have the lower-case extension .csv.
If you then want to combine those data frames into a single data frame, see the solutions in other answers using things like do.call(rbind,...), dplyr::bind_rows() or ...
Render a string in HTML and preserve spaces and linebreaks
...As part of that I have a description (retrieved from a db) that has spaces and new lines. When it is rendered the new lines and spaces are ignored by the html. I would like to encode those spaces and new lines so that they aren't ignored.
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Is there a Python function to determine which quarter of the year a date is in?
...ed to count from 1 instead;-).
Originally two answers, multiply upvoted and even originally accepted (both currently deleted), were buggy -- not doing the -1 before the division, and dividing by 4 instead of 3. Since .month goes 1 to 12, it's easy to check for yourself what formula is right:
fo...