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How to check if an email address exists without sending an email?
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VRFY user
You can issue a RCPT, and see if the mail is rejected.
MAIL FROM:<>
RCPT TO:<user@domain>
If the user doesn't exist, you'll get a 5.1.1 DSN. However, just because the email is not rejected, does not mean the user exists. Some server will silently discard requests like t...
git still shows files as modified after adding to .gitignore
...m -r --cached .idea/
When you commit the .idea/ directory will be removed from your git repository and the following commits will ignore the .idea/ directory.
PS: You could use .idea/ instead of .idea/* to ignore a directory. You can find more info about the patterns on the .gitignore man page.
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What is the purpose of the “final” keyword in C++11 for functions?
...rn already mentioned in a comment is that if you are overriding a function from a base class, then you cannot possibly mark it as non-virtual:
struct base {
virtual void f();
};
struct derived : base {
void f() final; // virtual as it overrides base::f
};
struct mostderived : derived {
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Using helpers in model: how do I include helper dependencies?
I'm writing a model that handles user input from a text area. Following the advice from http://blog.caboo.se/articles/2008/8/25/sanitize-your-users-html-input , I'm cleaning up the input in the model before saving to database, using the before_validate callback.
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Difference between TCP and UDP?
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From the Skullbox article:
TCP (Transmission Control Protocol) is the most commonly used protocol on the Internet.
The reason for this is because TCP offers error correction. When the TCP protocol is used there is a "guarant...
What Regex would capture everything from ' mark to the end of a line?
...ants to do. It serves as a reminder later that it is expecting everything from ' to the end of the line
– gnarf
May 6 '09 at 18:03
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How to install Android SDK Build Tools on the command line?
I want to setup the Android dev environment from command line, and encounter the following issue:
19 Answers
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Printing HashMap In Java
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keySet() only returns a set of keys from your hashmap, you should iterate this key set and the get the value from the hashmap using these keys.
In your example, the type of the hashmap's key is TypeKey, but you specified TypeValue in your generic for-loop, so...
Gson - convert from Json to a typed ArrayList
...y use TypeToken to load the json string into a custom object.
logs = gson.fromJson(br, new TypeToken<List<JsonLog>>(){}.getType());
Documentation:
Represents a generic type T.
Java doesn't yet provide a way to represent generic types, so this class does. Forces clients to cr...
Python loop that also accesses previous and next values
...lement, and end iterating at the last-but-one element. So index should run from 1 ... (l-1), not 0 ... l as you have here, and no need for the special-cased if-clauses. Btw, there is a parameter enumerate(..., start=1) but not for end. So we don't realy want to use enumerate().
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