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What is an index in SQL?
...refman/5.0/en/mysql-indexes.html
An index can be used to efficiently find all rows matching some column in your query and then walk through only that subset of the table to find exact matches. If you don't have indexes on any column in the WHERE clause, the SQL server has to walk through the whole ...
Why do most C developers use define instead of const? [duplicate]
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@C. Ross: Consistency. All manifest constants are usually defined with #defines. const is only used to indicate a read-only (access path to a) variable. I know, const in C is just plain broken :-)
– Bart van Ingen Schenau
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Parsing JSON from XmlHttpRequest.responseJSON
...ys II: responseType
As Londeren has written in his answer, newer browsers allow you to use the responseType property to define the expected format of the response. The parsed response data can then be accessed via the response property:
var req = new XMLHttpRequest();
req.responseType = 'json';
re...
How do I specify local .gem files in my Gemfile?
I have a couple of gem files which I install via gem install xx.gem . Can I tell Bundler to use them? Or do I have to specify the source path?
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How to get back to the latest commit after checking out a previous commit?
...o use git was not knowing what specific keywords (e.g. "master") I can actually substitute in for placeholder words like "branchname".
– AbePralle
Feb 2 '12 at 7:19
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Unable to simultaneously satisfy constraints, will attempt to recover by breaking constraint
...the memory pointers are the same. So we know what is going on now. Additionally you can find NSLayoutConstraint in view hierarchy. Since it is selected in View, it selected in Navigator also.
If you need you may also print it on console using address pointer:
(lldb) po 0x17dce920
<UIView: 0x1...
Showing line numbers in IPython/Jupyter Notebooks
...l line numbers. In more recent notebook versions Shift-L should toggle for all cells.
If you can't remember the shortcut, bring up the command palette Ctrl-Shift+P (Cmd+Shift+P on Mac), and search for "line numbers"), it should allow to toggle and show you the shortcut.
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How to get the list of properties of a class?
How do I get a list of all the properties of a class?
10 Answers
10
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Pointers in C: when to use the ampersand and the asterisk?
... work differently when you're working with arrays, strings or when you're calling functions with a pointer copy of a variable. It's difficult to see a pattern of logic inside all of this.
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Java logical operator short-circuiting
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In fact, to be really complete, all of &&, ||, & and | evaluate left to right. For a set of booleans b1, b2, ..., bn, the short circuit versions will cease evaluation when the first of these booleans is true (||) or false (&&a...