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How to UPSERT (MERGE, INSERT … ON DUPLICATE UPDATE) in PostgreSQL?
...o do an upsert, which is what MySQL calls INSERT ... ON DUPLICATE UPDATE and the standard supports as part of the MERGE operation.
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How does numpy.histogram() work?
...ere are 3 bins, for values ranging from 0 to 1 (excl 1.), 1 to 2 (excl. 2) and 2 to 3 (incl. 3), respectively. The way Numpy defines these bins if by giving a list of delimiters ([0, 1, 2, 3]) in this example, although it also returns the bins in the results, since it can choose them automatically f...
How can I mix LaTeX in with Markdown? [closed]
I've been using Markdown for class notes, and it's great. I even do some preprocessing on the Markdown so I can do things like tables. But this term I'm teaching a class with a lot of math, and I'd love to be able to put LaTeX formulas with Markdown, something like this:
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What are the applications of binary trees?
...ch applications where data is constantly entering/leaving, such as the map and set objects in many languages' libraries.
Binary Space Partition - Used in almost every 3D video game to determine what objects need to be rendered.
Binary Tries - Used in almost every high-bandwidth router for storing ro...
Difference between Lookup() and Dictionary(Of list())
...trying to wrap my head around which data structures are the most efficient and when / where to use which ones.
6 Answers
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Is there a query language for JSON?
... work in progress, but work to some degree. They are also similar to XPath and XQuery conceptually; even though XML and JSON have different conceptual models (hierarchic vs object/struct).
EDIT Sep-2015: Actually there is now JSON Pointer standard that allows very simple and efficient traversal of ...
PHP - Check if two arrays are equal
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$arraysAreEqual = ($a == $b); // TRUE if $a and $b have the same key/value pairs.
$arraysAreEqual = ($a === $b); // TRUE if $a and $b have the same key/value pairs in the same order and of the same types.
See Array Operators.
EDIT
The inequality operator is != whil...
How does IPython's magic %paste work?
I want to copy already indented Python code / whole functions and classes into IPython. Everytime I try the indentation is screwed up and I get following error message:
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Is there a performance gain in using single quotes vs double quotes in ruby?
...gle quotes in ruby decreases performance in any meaningful way in ruby 1.8 and 1.9.
14 Answers
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How do I import the javax.servlet API in my Eclipse project?
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Ensure you've the right Eclipse and Server
Ensure that you're using at least Eclipse IDE for Enterprise Java developers (with the Enterprise). It contains development tools to create dynamic web projects and easily integrate servletcontainers (those tools a...