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How to implement a Map with multiple keys? [duplicate]
I need a data structure which behaves like a Map,
but uses multiple (differently-typed) keys to access its values.
(Let's not be too general, let's say two keys)
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Python dict how to create key or append an element to key?
I have an empty dictionary. Name: dict_x
It is to have keys of which values are lists.
5 Answers
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Converting timestamp to time ago in PHP e.g 1 day ago, 2 days ago…
...timestamp of the format 2009-09-12 20:57:19 and turn it into something like 3 minutes ago with PHP.
30 Answers
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Database: To delete or not to delete records
I don't think I am the only person wondering about this. What do you usually practice about database behavior? Do you prefer to delete a record from the database physically? Or is it better to just flag the record with a "deleted" flag or a boolean column to denote the record is active or inactive?
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How can I determine if a JavaScript variable is defined in a page? [duplicate]
How can i check in JavaScript if a variable is defined in a page? Suppose I want to check if a variable named "x" is defined in a page, if I do if(x != null) , it gives me an error.
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R: Comment out block of code [duplicate]
...any way of doing it without having to put a # before each line - sort of like /* blocked out code */ in SAS?
5 Answers
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Inserting image into IPython notebook markdown
I am starting to depend heavily on the IPython notebook app to develop and document algorithms. It is awesome; but there is something that seems like it should be possible, but I can't figure out how to do it:
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Is there a fixed sized queue which removes excessive elements?
...there are two open implementations available (this answer is quite old, folks!), see this answer for details.
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How to escape single quotes in MySQL
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Put quite simply:
SELECT 'This is Ashok''s Pen.';
So inside the string, replace each single quote with two of them.
Or:
SELECT 'This is Ashok\'s Pen.'
Escape it =)
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Java Reflection Performance
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Yes - absolutely. Looking up a class via reflection is, by magnitude, more expensive.
Quoting Java's documentation on reflection:
Because reflection involves types that are dynamically resolved, certain Java virtual machine optimizations can...