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R command for setting working directory to source file location in Rstudio
... you should see the current working directory. To the right of that is a small arrow. Click that to show the current working directory in the file browser.
– Richie Cotton
Feb 20 at 15:40
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Ruby regular expression using variable name
...aracters. If it does and you want those matacharacters to do what they usually do in a regular expression, then the same gsub will work:
var = "Value|a|test"
str = "a test Value"
str.gsub( /#{var}/, 'foo' ) # => "foo foo foo"
However, if your search string contains metacharacters and you do n...
Check if a given key already exists in a dictionary
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I usually just use get if I'm going to be pulling the item out of the dictionary anyway. No sense in using in and pulling the item out of the dictionary.
– Jason Baker
Oct 21 '09 at 19:12
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How do I stop Chrome from yellowing my site's input boxes?
...ere's an error triggered, but it is a complex bit of coding to programmatically turn off the auto-complete for the single effected input on a page."
– Dave Rutledge
Oct 6 '08 at 21:54
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$watch an object
I want to watch for changes in a dictionary, but for some reason watch callback is not called.
8 Answers
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How is Generic Covariance & Contra-variance Implemented in C# 4.0?
...hat will become IEnumerable<out T>. That doesn't hurt type safety at all, but lets you return an IEnumerable<string> from a method declared to return IEnumerable<object> for instance.
Contravariance is harder to give concrete examples for using interfaces, but it's easy with a del...
Byte[] to InputStream or OutputStream
...it to InputStream or OutputStream . But I don't know what happens internally when I do so. Can anyone briefly explain me what's happening when I do this conversion?
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Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?
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@Jasen That's totally clear. Just wanted to emphasize that the answer "But if you have non-unique entries on your table. Here is the how to add unique constraint on your table." will not work. Non-unique entries must of course always be conso...
Difference between Python datetime vs time modules
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the time module is principally for working with unix time stamps; expressed as a floating point number taken to be seconds since the unix epoch. the datetime module can support many of the same operations, but provides a more object oriented set of t...
Small Haskell program compiled with GHC into huge binary
Even trivially small Haskell programs turn into gigantic executables.
2 Answers
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