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get dictionary value by key
...
It's as simple as this:
String xmlfile = Data_Array["XML_File"];
Note that if the dictionary doesn't have a key that equals "XML_File", that code will throw an exception. If you want to check first, you can use TryGetValue like this:
string xmlfile;
if (!Data_Array.Tr...
Why does ++[[]][+[]]+[+[]] return the string “10”?
...t the first element from [[]], it is true that:
[[]][0] returns the inner array ([]). Due to references it's wrong to say [[]][0] === [], but let's call the inner array A to avoid the wrong notation.
++ before its operand means “increment by one and return the incremented result”. So ++[[]][0]...
Difference between map and collect in Ruby?
... actually any difference between doing a map and doing a collect on an array in Ruby/Rails?
5 Answers
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Create an empty object in JavaScript with {} or new Object()?
... '/img/picture.jpg',
width: 300,
height: 200
};
Arrays
For arrays, there's similarly almost no benefit to ever using new Array(); over []; - with one minor exception:
var emptyArray = new Array(100);
creates a 100 item long array with all slots containing undefined - w...
What's the difference between echo, print, and print_r in PHP?
...f a variable, including its type and the type of any sub-items (if it's an array or an object). print_r prints a variable in a more human-readable form: strings are not quoted, type information is omitted, array sizes aren't given, etc.
var_dump is usually more useful than print_r when debugging, i...
Why does the order of the loops affect performance when iterating over a 2D array?
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As others have said, the issue is the store to the memory location in the array: x[i][j]. Here's a bit of insight why:
You have a 2-dimensional array, but memory in the computer is inherently 1-dimensional. So while you imagine your array like this:
0,0 | 0,1 | 0,2 | 0,3
----+-----+-----+----
1,0...
How to convert string to char array in C++?
I would like to convert string to char array but not char* . I know how to convert string to char* (by using malloc or the way I posted it in my code) - but that's not what I want. I simply want to convert string to char[size] array. Is it possible?
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Numpy matrix to array
...using numpy. I have a matrix with 1 column and N rows and I want to get an array from with N elements.
9 Answers
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How to check if array element exists or not in javascript?
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Use typeof arrayName[index] === 'undefined'
i.e.
if(typeof arrayName[index] === 'undefined') {
// does not exist
}
else {
// does exist
}
share
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String's Maximum length in Java - calling length() method
...^31 - 1 (or approximately 2 billion.)
In terms of lengths and indexing of arrays, (such as char[], which is probably the way the internal data representation is implemented for Strings), Chapter 10: Arrays of The Java Language Specification, Java SE 7 Edition says the following:
The variables c...