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Concatenating multiple text files into a single file in Bash
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This appends the output to all.txt
cat *.txt >> all.txt
This overwrites all.txt
cat *.txt > all.txt
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What is the difference between up-casting and down-casting with respect to class variable
...ClassCastExceptions:
Animal animal = getAnimal(); // Maybe a Dog? Maybe a Cat? Maybe an Animal?
if (animal instanceof Dog) {
// Guaranteed to succeed, barring classloader shenanigans
Dog castedDog = (Dog) animal;
}
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ArithmeticException: “Non-terminating decimal expansion; no exact representable decimal result”
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Check out this link :
http://edelstein.pebbles.cs.cmu.edu/jadeite/main.php?api=java6&state=class&package=java.math&class=MathContext
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Object.getOwnPropertyNames vs Object.keys
...s constructor when creating object. Here is something that got me.
const cat1 = {
eat() {},
sleep() {},
talk() {}
};
// here the methods will be part of the Cat Prototype
class Cat {
eat() {}
sleep() {}
talk() {}
}
const cat2 = new Cat()
Object.keys(cat1) // ["eat", "sle...
Concatenate multiple files but include filename as section headers
I would like to concatenate a number of text files into one large file in terminal. I know I can do this using the cat command. However, I would like the filename of each file to precede the "data dump" for that file. Anyone know how to do this?
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How can I copy the output of a command directly into my clipboard?
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You can then pipe the output into xclip to be copied into the clipboard:
cat file | xclip
To paste the text you just copied, you shall use:
xclip -o
To simplify life, you can set up an alias in your .bashrc file as I did:
alias "c=xclip"
alias "v=xclip -o"
To see how useful this is, imagin...
Local variables in nested functions
...me point during that execution was assigned each of the 'cow', 'dog', and 'cat' strings, but at the end of the function, cage contains that last value 'cat'. Thus, when you call each of the dynamically returned functions, you get the value 'cat' printed.
The work-around is to not rely on closures. ...
Programmatically creating Markdown tables in R with KnitR
...Banana"),size=40,replace=TRUE),
Var2=sample(x=c("Dog","Cat","Bunny"),size=40,replace=TRUE))
tbl1 <- table(my.df$Var1,my.df$Var2)
tbl1 <- cbind(tbl1,rowSums(tbl1))
tbl1 <- rbind(tbl1,colSums(tbl1))
colnames(tbl1)[4] <- "TOTAL"
rownames(tbl1)[4] <- "TOTAL"
# Beca...
Array extension to remove object by value
...omArray.filter { return $0 != object }
}
Sample:
var myArray = ["Dog", "Cat", "Ant", "Fish", "Cat"]
myArray = arrayRemovingObject("Cat", fromArray:myArray )
Swift 2 (xcode 7b4) array extension:
extension Array where Element: Equatable {
func arrayRemovingObject(object: Element) -> [Elem...
Is List a subclass of List? Why are Java generics not implicitly polymorphic?
...do with a List<Animal> - you can add any animal to it... including a cat. Now, can you logically add a cat to a litter of puppies? Absolutely not.
// Illegal code - because otherwise life would be Bad
List<Dog> dogs = new ArrayList<Dog>(); // ArrayList implements List
List<Anim...