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C++ unordered_map using a custom class type as the key
... things:
A hash function; this must be a class that overrides operator() and calculates the hash value given an object of the key-type. One particularly straight-forward way of doing this is to specialize the std::hash template for your key-type.
A comparison function for equality; this is require...
What encoding/code page is cmd.exe using?
...
Yes, it’s frustrating—sometimes type and other programs
print gibberish, and sometimes they do not.
First of all, Unicode characters will only display if the
current console font contains the characters. So use
a TrueType font like Lucida Console instead of the...
Using std Namespace
...ng namespace std;. It imports all sorts of names into the global namespace and can cause all sorts of non-obvious ambiguities.
Here are some common identifiers that are in the std namespace: count, sort, find, equal, reverse. Having a local variable called count means that using namespace std won't...
What's the nearest substitute for a function pointer in Java?
...gFunction sf) {
int i = sf.func("my string");
// do whatever ...
}
And would be called like so:
ref.takingMethod(new StringFunction() {
public int func(String param) {
// body
}
});
EDIT: In Java 8, you could call it with a lambda expression:
ref.takingMethod(param -> ...
What's the difference between using “let” and “var”?
...let keyword was introduced to the language was function scope is confusing and was one of the main sources of bugs in JavaScript.
Take a look at this example from another stackoverflow question:
var funcs = [];
// let's create 3 functions
for (var i = 0; i < 3; i++) {
// and store them in fun...
Remove an element from a Bash array
...
The following works as you would like in bash and zsh:
$ array=(pluto pippo)
$ delete=pluto
$ echo ${array[@]/$delete}
pippo
$ array=( "${array[@]/$delete}" ) #Quotes when working with strings
If need to delete more than one element:
...
$ delete=(pluto pippo)
for de...
How to get unique values in an array
...hat uses no libraries. This requires two new prototype functions, contains and unique
Array.prototype.contains = function(v) {
for (var i = 0; i < this.length; i++) {
if (this[i] === v) return true;
}
return false;
};
Array.prototype.unique = function() {
var arr = [];
...
What would cause an algorithm to have O(log n) complexity?
My knowledge of big-O is limited, and when log terms show up in the equation it throws me off even more.
6 Answers
...
How can I use if/else in a dictionary comprehension?
...ntioning that you don't need to have an if-else condition for both the key and the value. For example, {(a if condition else b): value for key, value in dict.items()} will work.
– Jeremy Weirich
Jul 26 '16 at 19:41
...
Difference between partition key, composite key and clustering key in Cassandra?
I have been reading articles around the net to understand the differences between the following key types. But it just seems hard for me to grasp. Examples will definitely help make understanding better.
...