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How accurately should I store latitude and longitude?
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Actually, equator is best case. One latitude and one longitude degree are the same size at the equator (69 miles), but one degree of longitude shrinks to zero as it approaches either of the poles. Here's a very nice explanation: nationalatlas.gov/articles/mapping/a_latl...
Java HashMap performance optimization / alternative
...or every object:
public int hashCode() {
// assume that both a and b are sorted
return a[0] + powerOf52(a[1], 1) + powerOf52(b[0], 2) + powerOf52(b[1], 3) + powerOf52(b[2], 4);
}
public static int powerOf52(byte b, int power) {
int result = b;
for (int i = 0; i < p...
Normalize data in pandas
Suppose I have a pandas data frame df :
5 Answers
5
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How do I get whole and fractional parts from double in JSP/Java?
How do I get whole and fractional parts from double in JSP/Java ? If the value is 3.25 then I want to get fractional =.25 , whole = 3
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Convert absolute path into relative path given a current directory using Bash
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It's a pity that the package is outdated on Ubuntu 14.04 and does not have the --relative-to option.
– kzh
Jul 21 '16 at 15:18
3
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How to sort an array in Bash
...set IFS
Supports whitespace in elements (as long as it's not a newline), and works in Bash 3.x.
e.g.:
$ array=("a c" b f "3 5")
$ IFS=$'\n' sorted=($(sort <<<"${array[*]}")); unset IFS
$ printf "[%s]\n" "${sorted[@]}"
[3 5]
[a c]
[b]
[f]
Note: @sorontar has pointed out that care is re...
COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
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Bottom Line
Use either COUNT(field) or COUNT(*), and stick with it consistently, and if your database allows COUNT(tableHere) or COUNT(tableHere.*), use that.
In short, don't use COUNT(1) for anything. It's a one-trick pony, which rarely does what you want, and in those ...
Simple way to transpose columns and rows in SQL?
How do I simply switch columns with rows in SQL?
Is there any simple command to transpose?
9 Answers
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Difference between MEAN.js and MEAN.io
... noticed that there are two different stacks with either their own website and installation methods: mean.js and mean.io. So I came up asking myself this question: "Which one do I use?".
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Looking for a good world map generation algorithm [closed]
I'm working on a Civilization-like game and I'm looking for a good algorithm for generating Earth-like world maps. I've experimented with a few alternatives, but haven't hit on a real winner yet.
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