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Finding quaternion representing the rotation from one vector to another
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117
Quaternion q;
vector a = crossproduct(v1, v2);
q.xyz = a;
q.w = sqrt((v1.Length ^ 2) * (v2.Len...
Getting list of lists into pandas DataFrame
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271
Call the pd.DataFrame constructor directly:
df = pd.DataFrame(table, columns=headers)
df
He...
How do I create test and train samples from one dataframe with pandas?
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I would just use numpy's randn:
In [11]: df = pd.DataFrame(np.random.randn(100, 2))
In [12]: msk = np.random.rand(len(df)) < 0.8
In [13]: train = df[msk]
In [14]: test = df[~msk]
And just to see this has worked:
In [15]: len(test)
Out[15]: 21
In [16]:...
startsWith() and endsWith() functions in PHP
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Is there a NumPy function to return the first index of something in an array?
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13 Answers
13
Active
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libcurl的使用总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
...这里，方便给同样刚入门的朋友指引。
一.下载安装
1.到http://curl.haxx.se/download.html上下载最新版本，由于公司的机器安装rpm有依赖关系，所以直接下载了source
2.编译。解压后进入curl的目录，直接执行 make all 就行。
3....
Understanding recursion [closed]
...ot empty, you take out one flower
and then you empty a vase containing N-1 flowers.
Hmm, can we see that in code?
void emptyVase( int flowersInVase ) {
if( flowersInVase > 0 ) {
// take one flower and
emptyVase( flowersInVase - 1 ) ;
} else {
// the vase is empty, nothing to do...
Shading a kernel density plot between two points.
... the quantile values to get the actual (x,y) pairs.
Edit: Here you go:
x1 <- min(which(dens$x >= q75))
x2 <- max(which(dens$x < q95))
with(dens, polygon(x=c(x[c(x1,x1:x2,x2)]), y= c(0, y[x1:x2], 0), col="gray"))
Output (added by JDL)
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str performance in python
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105
'%s' % 100000 is evaluated by the compiler and is equivalent to a constant at run-time.
>&...