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What is a 'Closure'?
...ope when the function was first defined to still be in scope when we later call the function, even if we call the function in a completely different context.
For example
Here's a really simple example in JavaScript that illustrates the point:
outer = function() {
var a = 1;
var inner = functi...
How can I hash a password in Java?
...ception;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.util.Arrays;
import java.util.Base64;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.crypto.SecretKeyFactory;
import javax.cryp...
What do 'real', 'user' and 'sys' mean in the output of time(1)?
... the process.
Real is wall clock time - time from start to finish of the call. This is all elapsed time including time slices used by other processes and time the process spends blocked (for example if it is waiting for I/O to complete).
User is the amount of CPU time spent in user-mode code (out...
How to call an external command?
How do you call an external command (as if I'd typed it at the Unix shell or Windows command prompt) from within a Python script?
...
Zoom in on a point (using scale and translate)
...iner + currentTranslation). This math also assumes the origin point is typically in the upper left of the field. But, adjusting for slightly atypical situations is much easier given the simplicity.
– Tatarize
Feb 1 '16 at 8:52
...
All permutations of a Windows license key
...eters partial is not required when using format as it changes nothing when called without *args or **kwargs. When using format you can not pass the tuple directly but need to convert it to arguments first: map(lambda args: 'MPP6R-09RXG-2H{}MT-{}K{}M9-V{}C8R'.format(*args), product('8B', 'B8', 'HN', ...
What is two way binding?
...eners). Other frameworks like Knockout do wire up two-way binding automagically.
In Backbone, you can easily achieve #1 by binding a view's "render" method to its model's "change" event. To achieve #2, you need to also add a change listener to the input element, and call model.set in the handl...
How to read json file into java with simple JSON library
...
I have tried that but it did not work. Can you give me a code example
– billz
Jun 7 '12 at 8:22
3
...
What and where are the stack and heap?
... set aside as scratch space for a thread of execution. When a function is called, a block is reserved on the top of the stack for local variables and some bookkeeping data. When that function returns, the block becomes unused and can be used the next time a function is called. The stack is always...
Objective-C declared @property attributes (nonatomic, copy, strong, weak)
...e retaining the copy.
Assign
Assign is somewhat the opposite to copy. When calling the getter of an assign property, it returns a reference to the actual data. Typically you use this attribute when you have a property of primitive type (float, int, BOOL...)
Retain
retain is required when the attribu...