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Check if an element is present in an array [duplicate]
...ates an includes() method for arrays that specifically solves the problem, and so is now the preferred method.
[1, 2, 3].includes(2); // true
[1, 2, 3].includes(4); // false
[1, 2, 3].includes(1, 2); // false (second parameter is the index position in this array at which to begin searching...
Permutations in JavaScript?
...s into an array prior to do any permutation, so you simply remove the join and split operation
var permArr = [],
usedChars = [];
function permute(input) {
var i, ch;
for (i = 0; i < input.length; i++) {
ch = input.splice(i, 1)[0];
usedChars.push(ch);
if (input.leng...
Why does range(start, end) not include end?
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You explain that range(x) should start with 0 and x will be the "length of the range". OK. But you didn't explain why range(x,y) should start with x and end with y-1. If the programmer wants a for-loop with i ranging from 1 to 3, he has to explicitly add 1. Is this reall...
Getting a map() to return a list in Python 3.x
I'm trying to map a list into hex, and then use the list elsewhere. In python 2.6, this was easy:
9 Answers
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How can I sort a dictionary by key?
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Standard Python dictionaries are unordered. Even if you sorted the (key,value) pairs, you wouldn't be able to store them in a dict in a way that would preserve the ordering.
The easiest way is to use OrderedDict, which remembe...
Using boolean values in C
...e 1
#define false 0
Explanation
Option 1 will work only if you use C99 and it's the "standard way" to do it. Choose this if possible.
Options 2, 3 and 4 will have in practice the same identical behavior. #2 and #3 don't use #defines though, which in my opinion is better.
If you are undecided, ...
What do linkers do?
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To understand linkers, it helps to first understand what happens "under the hood" when you convert a source file (such as a C or C++ file) into an executable file (an executable file is a file that can be executed on your machine or so...
What does the JSLint error 'body of a for in should be wrapped in an if statement' mean?
...sole.log([0, 5, 0, 3, 0, 1, 0].filter_0());
//prints [5,3,1]
This is a standard way to extend objects and add new methods. Lots of libraries do this.
However, let's look at how for in works now:
var listeners = ["a", "b", "c"];
for (o in listeners) {
console.log(o);
}
//prints:
// 0
// 1
//...
Bash tool to get nth line from a file
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head and pipe with tail will be slow for a huge file. I would suggest sed like this:
sed 'NUMq;d' file
Where NUM is the number of the line you want to print; so, for example, sed '10q;d' file to print the 10th line of file.
Ex...
How to check whether a file is empty or not?
... that's fine too. but i don't want to import stat. Its short and sweet enough and the size position in the returned list is not going to change anytime soon.
– ghostdog74
Mar 24 '10 at 13:48
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