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How to sum a variable by group
...umns. First column contains categories such as "First", "Second", "Third", and the second column has numbers that represent the number of times I saw the specific groups from "Category".
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Fastest Way to Find Distance Between Two Lat/Long Points
...have just under a million locations in a mysql database all with longitude and latitude information.
15 Answers
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Why is null an object and what's the difference between null and undefined?
...n short; undefined is where no notion of the thing exists; it has no type, and it's never been referenced before in that scope; null is where the thing is known to exist, but it's not known what the value is.
One thing to remember is that null is not, conceptually, the same as false or "" or such, e...
Generating v5 UUID. What is name and namespace?
I've read the man page, but I do not undestand what name and namespace are for.
3 Answers
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Displaying the build date
... have an app displaying the build number in its title window. That's well and good except it means nothing to most of the users, who want to know if they have the latest build - they tend to refer to it as "last Thursday's" rather than build 1.0.8.4321.
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Change column type from string to float in Pandas
I want to convert a table, represented as a list of lists, into a Pandas DataFrame . As an extremely simplified example:
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Div width 100% minus fixed amount of pixels
...hout using tables or JavaScript? The white borders represent edges of divs and aren't relevant to the question.
10 Answers
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Remove duplicate rows in MySQL
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The aforementioned bug @DarkMantis referred to and it's solution.
– Jordan Arseno
Jan 23 '13 at 20:47
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Restoring MySQL database from physical files
... this is true only for MyISAM tables. InnoDB stores its tables and indexes in a single tablespace *, which by default consist of the 3 files ibdata1, ib_logfile0, and ib_logfile1. for restoring a database, you would also need those files. * per-table tablespaces are possible, but not de...
Excel: last character/string match in a string
... position of a character/string's last occurrence in a string. Search and find both work left-to-right so I can't think how to apply without lengthy recursive algorithm. And this solution now seems obsolete.
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