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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...
What are Scala context and view bounds?
...ch are Java classes, like they were Scala collections. For example:
def f[CC <% Traversable[_]](a: CC, b: CC): CC = if (a.size < b.size) a else b
If one tried to do this without view bounds, the return type of a String would be a WrappedString (Scala 2.8), and similarly for Array.
The same...
Convert string to symbol-able in ruby
...usly exist. See Symbol#id2name.
"Koala".intern #=> :Koala
s = 'cat'.to_sym #=> :cat
s == :cat #=> true
s = '@cat'.to_sym #=> :@cat
s == :@cat #=> true
This can also be used to create symbols that cannot be represented using the :xxx notat...
How can I convert an image into Base64 string using JavaScript?
...ob';
xhr.send();
}
toDataURL('https://www.gravatar.com/avatar/d50c83cc0c6523b4d3f6085295c953e0', function(dataUrl) {
console.log('RESULT:', dataUrl)
})
This code example could also be implemented using the WHATWG fetch API:
const toDataURL = url => fetch(url)
.then(respo...
How to concatenate stdin and a string?
How to I concatenate stdin to a string, like this?
9 Answers
9
...
How to remove an element from an array in Swift
...ant to modify a variable you should use var instead, e.g:
var animals = ["cats", "dogs", "chimps", "moose"]
animals.remove(at: 2) //["cats", "dogs", "moose"]
A non-mutating alternative that will keep the original collection unchanged is to use filter to create a new collection without the eleme...
How to pass the value of a variable to the stdin of a command?
..."$blah"? With that one change (avoiding the many pitfalls in echo's specification, which Stephane's excellent answer goes into in detail at Why is printf better than echo? on Unix & Linux, or which the APPLICATION USAGE section of the echo specification touches on more briefly) it's a perfectly ...
cannot download, $GOPATH not set
.../Homebrew/homebrew/blob/master/Library/Formula/go.rb
==> Options
--with-cc-all
Build with cross-compilers and runtime support for all supported platforms
--with-cc-common
Build with cross-compilers and runtime support for darwin, linux and windows
--without-cgo
Build without cgo
--wit...
What is the difference between shallow copy, deepcopy and normal assignment operation?
...
>>> hex(id(i)), hex(id(j))
>>> ('0x102b9b7c8', '0x102971cc8') #Both addresses are different
>>> i.append(4)
>>> j
>>> [1,2,3] #Updation of original list didn't affected copied variable
Nested list example using copy:
>>> import copy
>>...
How to read a file into a variable in shell?
...In cross-platform, lowest-common-denominator sh you use:
#!/bin/sh
value=`cat config.txt`
echo "$value"
In bash or zsh, to read a whole file into a variable without invoking cat:
#!/bin/bash
value=$(<config.txt)
echo "$value"
Invoking cat in bash or zsh to slurp a file would be considered a...