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What are the mathematical/computational principles behind this game?
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150
Finite Projective Geometries
The axioms of projective (plane) geometry are slightly different ...
How do I replace NA values with zeros in an R dataframe?
...nt in @gsk3 answer. A simple example:
> m <- matrix(sample(c(NA, 1:10), 100, replace = TRUE), 10)
> d <- as.data.frame(m)
V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1 4 3 NA 3 7 6 6 10 6 5
2 9 8 9 5 10 NA 2 1 7 2
3 1 1 6 3 6 NA 1 4 1 6
4 NA 4 NA 7 10 2 NA 4 1...
What do hjust and vjust do when making a plot using ggplot?
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The value of hjust and vjust are only defined between 0 and 1:
0 means left-justified
1 means right-justified
Source: ggplot2, Hadley Wickham, page 196
(Yes, I know that in most cases you can use it beyond this range, but don't expect it to behave in any specific way. This...
汇编常用寄存器及指令基础总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
汇编常用寄存器及指令基础总结8086汇编常用寄存器数据寄存器AH&AL=AX：累加寄存器，常用于运算BH&BL=BX：基址寄存器，常用于地址索引CH&CL=CX：计数寄存器，常用于计数DH...8086汇编常用寄存器
数据寄存器
AH&AL=AX：累加寄存器，...
Is there a better way of writing v = (v == 0 ? 1 : 0); [closed]
I want to toggle a variable between 0 and 1. If it's 0 I want to set it to 1, else if it's 1 I want to set it to 0.
31 Answ...
Performance of foreach, array_map with lambda and array_map with static function
...W, I just did the benchmark since poster didn't do it. Running on PHP 5.3.10 + XDebug.
UPDATE 2015-01-22 compare with mcfedr's answer below for additional results without XDebug and a more recent PHP version.
function lap($func) {
$t0 = microtime(1);
$numbers = range(0, 1000000);
$ret = $f...
Getting the array length of a 2D array in Java
... };
System.out.println(foo.length); //2
System.out.println(foo[0].length); //3
System.out.println(foo[1].length); //4
}
Column lengths differ per row. If you're backing some data by a fixed size 2D array, then provide getters to the fixed values in a wrapper class.
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What does this square bracket and parenthesis bracket notation mean [first1,last1)?
...rst1 (and includes it), but ends just before last1.
Assuming integers:
(0, 5) = 1, 2, 3, 4
(0, 5] = 1, 2, 3, 4, 5
[0, 5) = 0, 1, 2, 3, 4
[0, 5] = 0, 1, 2, 3, 4, 5
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Remove empty elements from an array in Javascript
...xample, if you want to remove null or undefined values:
var array = [0, 1, null, 2, "", 3, undefined, 3,,,,,, 4,, 4,, 5,, 6,,,,];
var filtered = array.filter(function (el) {
return el != null;
});
console.log(filtered);
It will depend on what you consider to be "empty" for exa...
How do I include negative decimal numbers in this regular expression?
...e with positive values, but I want it to also allow negative values e.g. -10, -125.5 etc.
14 Answers
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