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Adding 'serial' to existing column in Postgres
I have a small table (~30 rows) in my Postgres 9.0 database with an integer ID field (the primary key) which currently contains unique sequential integers starting at 1, but which was not created using the 'serial' keyword.
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Removing all empty elements from a hash / YAML?
How would I go about removing all empty elements (empty list items) from a nested Hash or YAML file?
20 Answers
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How do I provide JVM arguments to VisualVM?
I'm using VisualVM from JDK 1.6.0_26 to profile a Java webapp running under Tomcat, but VisualVM often tells me that it doesn't have enough memory to take a snapshot, and to use the -Xmx switch to provide more memory to Netbeans. The problem is, I'm running VisualVM outside of Netbeans, so how can I...
When exactly is it leak safe to use (anonymous) inner classes?
...y tough question. While you may think it is just one question, you are actually asking several questions at once. I'll do my best with the knowledge that I have to cover it and, hopefully, some others will join in to cover what I may miss.
Nested Classes: Introduction
As I'm not sure how comfortab...
What are my environment variables? [closed]
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I am not sure if thats what you want, but try printenv
This will show you all your environment variables.
About where they are stored
Linux: where are environment variables stored?
How to set Shell Environment Variables
http://www.codecoffee.com/tipsforlinux/articles/030.html
Happy reading :-)...
Detect backspace in empty UITextField
...yTextField
- (void)deleteBackward {
[super deleteBackward];
if ([_myDelegate respondsToSelector:@selector(textFieldDidDelete)]){
[_myDelegate textFieldDidDelete];
}
}
@end
Now simply add MyTextFieldDelegate to your UIViewController and set your UITextFields myDelegate to sel...
Examples of Algorithms which has O(1), O(n log n) and O(log n) complexities
...p of Statements with Time complexity as given in the question, here is a small list -
O(1) time
Accessing Array Index (int a = ARR[5];)
Inserting a node in Linked List
Pushing and Poping on Stack
Insertion and Removal from Queue
Finding out the parent or left/right child of a node in a tree store...
How do I send a cross-domain POST request via JavaScript?
...e.php (using PHP as an example). Note: you only need to set Access-Control-Allow-Origin for NON OPTIONS requests - this example always sets all headers for a smaller code snippet.
In postHere.php setup the following:
switch ($_SERVER['HTTP_ORIGIN']) {
case 'http://from.com': case 'https://fro...
How to get a substring between two strings in PHP?
...ieves that. I do not want to think about regex (well, I could do one but really don't think it's the best way to go). Thinking of strpos and substr functions.
Here's an example:
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Generating all permutations of a given string
What is an elegant way to find all the permutations of a string. E.g. permutation for ba , would be ba and ab , but what about longer string such as abcdefgh ? Is there any Java implementation example?
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