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Checking if a key exists in a JavaScript object?
How do I check if a particular key exists in a JavaScript object or array?
22 Answers
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(Built-in) way in JavaScript to check if a string is a valid number
I'm hoping there's something in the same conceptual space as the old VB6 IsNumeric() function?
37 Answers
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What does 'predicate' mean in the context of computer science? [duplicate]
Specifically I've seen it used in the context of text filtering. As if "predicate" == "filter criteria".
7 Answers
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Apply a function to every row of a matrix or a data frame
Suppose I have a n by 2 matrix and a function that takes a 2-vector as one of its arguments. I would like to apply the function to each row of the matrix and get a n-vector. How to do this in R?
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Are braces necessary in one-line statements in JavaScript?
I once heard that leaving the curly braces in one-line statements could be harmful in JavaScript. I don't remember the reasoning anymore and a Google search did not help much.
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How do I remove a property from a JavaScript object?
Say I create an object as follows:
46 Answers
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What is Virtual DOM?
Recently, I looked at Facebook's React framework. It uses a concept called "the Virtual DOM," which I didn't really understand.
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How are parameters sent in an HTTP POST request?
In an HTTP GET request, parameters are sent as a query string :
8 Answers
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What is the difference between a symbolic link and a hard link?
Recently I was asked this during a job interview. I was honest and said I knew how a symbolic link behaves and how to create one, but do not understand the use of a hard link and how it differs from a symbolic one.
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How is Docker different from a virtual machine?
I keep rereading the Docker documentation to try to understand the difference between Docker and a full VM. How does it manage to provide a full filesystem, isolated networking environment, etc. without being as heavy?
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