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How do I enumerate the properties of a JavaScript object? [duplicate]

...till confuse me a bit. Again, inheritance is a normal part of OO languages and is therefore part of JavaScript, notwithstanding it being prototypical. Now, that said, hasOwnProperty() is useful for filtering, but we don't need to sound a warning as if there is something dangerous in getting inherit...
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How to check if an email address exists without sending an email?

...determine if a recipient actually exists: You can connect to the server, and issue a VRFY command. Very few servers support this command, but it is intended for exactly this. If the server responds with a 2.0.0 DSN, the user exists. VRFY user You can issue a RCPT, and see if the mail is rejected...
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What is the 'cls' variable used for in Python classes?

... The distinction between "self" and "cls" is defined in PEP 8 . As Adrien said, this is not a mandatory. It's a coding style. PEP 8 says: Function and method arguments: Always use self for the first argument to instance methods. Always use cls for the firs...
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Accessing the web page's HTTP Headers in JavaScript

...o read the current headers. You could make another request to the same URL and read its headers, but there is no guarantee that the headers are exactly equal to the current. Use the following JavaScript code to get all the HTTP headers by performing a get request: var req = new XMLHttpRequest();...
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How can I create a keystore?

What are the steps to create a keystore for android? 11 Answers 11 ...
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What generates the “text file busy” message in Unix?

... Use lsof to check what other processes are using it. You can use kill command to kill it if needed. share | improve this answer | follow | ...
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Install Application programmatically on Android

...ble to programmatically install a dynamically downloaded apk from a custom Android application. 16 Answers ...
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Allow user to set up an SSH tunnel, but nothing else

... On Ubuntu 11.10, I found I could block ssh commands, sent with and without -T, and block scp copying, while allowing port forwarding to go through. Specifically I have a redis-server on "somehost" bound to localhost:6379 that I wish to share securely via ssh tunnels to ...
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Is there a practical use for weak references? [duplicate]

...ta. It can also be used to keep information about objects used else where and you don't know when those objects are discarded. BTW Soft References are like Weak references, but they will not always be cleaned up immediately. The GC will always discard weak references when it can and retain Soft R...
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What's the correct way to sort Python `import x` and `from x import y` statements?

... Imports are generally sorted alphabetically and described in various places beside PEP 8. Alphabetically sorted modules are quicker to read and searchable. After all python is all about readability. Also It is easier to verify that something is imported, and avoids du...