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Fetch frame count with ffmpeg
...below.
ffprobe: Query the container
ffprobe -v error -select_streams v:0 -show_entries stream=nb_frames -of default=nokey=1:noprint_wrappers=1 input.mp4
This is a fast method.
Not all formats (such as Matroska) will report the number of frames resulting in the output of N/A. See the other met...
How to initialize an array's length in JavaScript?
..., e.g.
var data = [];
var length = 5; // user defined length
for(var i = 0; i < length; i++) {
data.push(createSomeObject());
}
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Given an array of numbers, return array of products of all other numbers (no division)
...
260
An explanation of polygenelubricants method is:
The trick is to construct the arrays (in the c...
How to debug a GLSL shader?
...
answered Mar 24 '10 at 17:14
Mr. BernaMr. Berna
10.1k11 gold badge3737 silver badges4141 bronze badges
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How can I sort arrays and data in PHP?
...te a comparison function. That function takes two elements and must return 0 if these elements are considered equal, a value lower than 0 if the first value is lower and a value higher than 0 if the first value is higher. That's all that's needed:
function cmp(array $a, array $b) {
if ($a['foo']...
From ND to 1D arrays
...c = a.flatten()
If you just want an iterator, use np.ndarray.flat:
In [20]: d = a.flat
In [21]: d
Out[21]: <numpy.flatiter object at 0x8ec2068>
In [22]: list(d)
Out[22]: [1, 2, 3, 4, 5, 6]
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pyplot scatter plot marker size
...xamples and the output they produce.
# doubling the width of markers
x = [0,2,4,6,8,10]
y = [0]*len(x)
s = [20*4**n for n in range(len(x))]
plt.scatter(x,y,s=s)
plt.show()
gives
Notice how the size increases very quickly. If instead we have
# doubling the area of markers
x = [0,2,4,6,8,10]
y ...
Find the max of two or more columns with pandas
...df = pd.DataFrame({"A": [1,2,3], "B": [-2, 8, 1]})
>>> df
A B
0 1 -2
1 2 8
2 3 1
>>> df[["A", "B"]]
A B
0 1 -2
1 2 8
2 3 1
>>> df[["A", "B"]].max(axis=1)
0 1
1 8
2 3
and so:
>>> df["C"] = df[["A", "B"]].max(axis=1)
>>> df
...
Ruby on Rails and Rake problems: uninitialized constant Rake::DSL
...
A tweet from DHH earlier. Rake .9.0 breaks Rails and several other things, you need to:
gem "rake", "0.8.7"
in your Gemfile.
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How many double numbers are there between 0.0 and 1.0?
...e), there will therefore be 2 to the 52th power different doubles (i.e., 4503599627370496 of them). For example, that's the number of distinct doubles between 0.5 included and 1.0 excluded, and exactly that many also lie between 1.0 included and 2.0 excluded, and so forth.
Counting the doubles bet...