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Hidden features of Scala
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trait Functor[F[_]] {
def fmap[A, B](f: A => B, fa: F[A]): F[B]
}
Now, if you have a Functor[List], you can map over lists. If you have a Functor[Tree], you can map over trees. But more importantly, if you have Functor[A] for any A of kind (*->*), you can map a function over A.
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Escape a string for a sed replace pattern
...PED_REPLACE=$(printf '%s\n' "$REPLACE" | sed -e 's/[\/&]/\\&/g')
# Now you can use ESCAPED_REPLACE in the original sed statement
sed "s/KEYWORD/$ESCAPED_REPLACE/g"
If you ever need to escape the KEYWORD string, the following is the one you need:
sed -e 's/[]\/$*.^[]/\\&/g'
And can be...
How do I get a file extension in PHP?
...uilt-in function to do that and not PHP (I am looking at Pythonistas right now :-)).
In fact, it does exist, but few people know it. Meet pathinfo():
$ext = pathinfo($filename, PATHINFO_EXTENSION);
This is fast and built-in. pathinfo() can give you other information, such as canonical path, depe...
How to fix committing to the wrong Git branch?
...ure
git stash pop # skip if all changes were committed
Now you have your master branch equals to origin/master and all new commits are on my_feature. Note that my_feature is a local branch, not a remote one.
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How do I show a console output/window in a forms application?
...s that changing this mysterious Visual Studio setting does). Does anyone know how this works under the hood?
– uglycoyote
Aug 14 '18 at 22:45
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Abstract methods in Python [duplicate]
...e with Python. While the concept seems too easy for me in Java yet up till now I have been unable to understand in Python which is surprising to me at least.
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rbenv not changing ruby version
... by rbenv ( be sure you have the eval statement above in .bash_profile!). Now, all works as before. Thanks for helping me get this solved.
– John Wooten
Jul 11 '19 at 14:44
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Make the current Git branch a master branch
...time they want to pull, else git will try to merge the changes into their (now) divergent local. The dangers of this are explained more in this answer
– 7yl4r
Mar 27 '17 at 14:56
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How to add Options Menu to Fragment in Android
....MenuInflater; instead of import android.support.v4.view.MenuInflater; and now all is working
– misterbassman
Nov 29 '11 at 10:53
185
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How to asynchronously call a method in Java
...ot (yet) have first-class functions, so this is the state of the art right now.
– shadit
Dec 4 '09 at 5:11
thanks for ...