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Dynamically select data frame columns using $ and a character value
I have a vector of different column names and I want to be able to loop over each of them to extract that column from a data.frame. For example, consider the data set mtcars and some variable names stored in a character vector cols . When I try to select a variable from mtcars using a dynamic s...
Difference between two lists
...Using Except is exactly the right way to go. If your type overrides Equals and GetHashCode, or you're only interested in reference type equality (i.e. two references are only "equal" if they refer to the exact same object), you can just use:
var list3 = list1.Except(list2).ToList();
If you need t...
What exactly is an HTTP Entity?
...majority of an HTTP request or response, consisting of some of the headers and the body, if present. It seems to be the entire request or response without the request or status line (although only certain header fields are considered part of the entity).
To illustrate; here's a request:
POST /foo...
Replace a string in a file with nodejs
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Sure, but do I have to read the file replace the text and then write the file again, or is there an easier way, sorry I'm more of a frontend guy.
– Andreas Köberle
Jan 6 '13 at 12:50
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Updating packages in Emacs
... type package-list-packages, which will take you to the *Packages* buffer (and also update the list of packages), and then type U x.
package-refresh-contents unconditionally tries to download a package list from all repos you've added to package-archives; package-archive-contents is non nil if yo...
How to break out from a ruby block?
...fers control out of the block, out of the iterator that invoked the block, and to the first expression following the invocation of the iterator:
f.each do |line| # Iterate over the lines in file f
break if line == "quit\n" # If this break statement is executed...
puts eval(line)
en...
How can I count all the lines of code in a directory recursively?
We've got a PHP application and want to count all the lines of code under a specific directory and its subdirectories. We don't need to ignore comments, as we're just trying to get a rough idea.
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How can I multiply and divide using only bit shifting and adding?
How can I multiply and divide using only bit shifting and adding?
14 Answers
14
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How to remove EXIF data without recompressing the JPEG?
... If you really trust the program add -overwrite_original switch and the program will not create the backup files.
– Salman A
Jul 31 '15 at 18:35
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json_encode is returning NULL?
...ranca on the web. Instead of cluttering the API with additional parameters and overhead, PHP (rigthly) uses the most common encoding, leaving to you the conversion burden if you use an uncommon (or an almost dead, as in your case) encoding.
– ntd
Nov 1 '13 at 1...