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How do I write stderr to a file while using “tee” with a pipe?
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I'm assuming you want to still see STDERR and STDOUT on the terminal. You could go for Josh Kelley's answer, but I find keeping a tail around in the background which outputs your log file very hackish and cludgy. Notice how you need to keep an exra FD and do cleanu...
Efficient way to apply multiple filters to pandas DataFrame or Series
I have a scenario where a user wants to apply several filters to a Pandas DataFrame or Series object. Essentially, I want to efficiently chain a bunch of filtering (comparison operations) together that are specified at run-time by the user.
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Why is Go so slow (compared to Java)?
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The 6g and 8g compilers are not particularly optimising, so the code they produce isn't particularly fast.
They're designed to run fast themselves and produce code that's OK (there is a bit of optimisation). gccgo uses GCC's existi...
Looking for a clear definition of what a “tokenizer”, “parser” and...
I am looking for a clear definition of what a "tokenizer", "parser" and "lexer" are and how they are related to each other (e.g., does a parser use a tokenizer or vice versa)? I need to create a program will go through c/h source files to extract data declaration and definitions.
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Is there any performance gain in indexing a boolean field?
... think about it like a book. If there were only 3 kinds of words in a book and you index all of them, you would have the same number of index pages as normal pages.
There would be a performance gain if there are relatively few records of one value. For example, if you have 1000 records and 10 of t...
Why is i++ not atomic?
...crement operation atomic; it involves synchronization at both the software and hardware levels that need not be present in an ordinary increment.
You could make the argument that i++ should have been designed and documented as specifically performing an atomic increment, so that a non-atomic increm...
How can I sharpen an image in OpenCV?
... Wikipedia article on unsharp masking:
You use a Gaussian smoothing filter and subtract the smoothed version from the original image (in a weighted way so the values of a constant area remain constant).
To get a sharpened version of frame into image: (both cv::Mat)
cv::GaussianBlur(frame, image, cv:...
javascript: recursive anonymous function?
...ive the function a name, even when you're creating the function as a value and not a "function declaration" statement. In other words:
(function foo() { foo(); })();
is a stack-blowing recursive function. Now, that said, you probably don't may not want to do this in general because there are som...
Why is rbindlist “better” than rbind?
I am going through documentation of data.table and also noticed from some of the conversations over here on SO that rbindlist is supposed to be better than rbind .
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Difference in Months between two dates in JavaScript
..." is subject to a lot of interpretation. :-)
You can get the year, month, and day of month from a JavaScript date object. Depending on what information you're looking for, you can use those to figure out how many months are between two points in time.
For instance, off-the-cuff:
function monthDif...