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.toArray(new MyClass[0]) or .toArray(new MyClass[myList.size()])?
...est version, on Hotspot 8, is:
MyClass[] arr = myList.toArray(new MyClass[0]);
I have run a micro benchmark using jmh the results and code are below, showing that the version with an empty array consistently outperforms the version with a presized array. Note that if you can reuse an existing arr...
Get ffmpeg information in friendly way
... would yield something like the following:
{
"streams": [{
"index": 0,
"codec_name": "wmv3",
"codec_long_name": "Windows Media Video 9",
"codec_type": "video",
"codec_time_base": "1/1000",
"codec_tag_string": "WMV3",
"codec_tag": "0x33564d57",
"width": 320,
"he...
How to change the opacity (alpha, transparency) of an element in a canvas element after it has been
...
309
I am also looking for an answer to this question, (to clarify, I want to be able to draw an ima...
Use HTML5 to resize an image before upload
...tos = function(url){
// Read in file
var file = event.target.files[0];
// Ensure it's an image
if(file.type.match(/image.*/)) {
console.log('An image has been loaded');
// Load the image
var reader = new FileReader();
reader.onload = function (reader...
Peak signal detection in realtime timeseries data
...core at which the algorithm signals and influence = the influence (between 0 and 1) of new signals on the mean and standard deviation. For example, a lag of 5 will use the last 5 observations to smooth the data. A threshold of 3.5 will signal if a datapoint is 3.5 standard deviations away from the m...
JavaScript function similar to Python range()
...ned') {
// one param defined
stop = start;
start = 0;
}
if (typeof step == 'undefined') {
step = 1;
}
if ((step > 0 && start >= stop) || (step < 0 && start <= stop)) {
return [];
}
var result = [];
for...
What is IP address '::1'?
...1 is the loopback address in IPv6. Think of it as the IPv6 version of 127.0.0.1.
See http://en.wikipedia.org/wiki/Localhost
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Multiple aggregations of the same column using pandas GroupBy.agg()
...
You can simply pass the functions as a list:
In [20]: df.groupby("dummy").agg({"returns": [np.mean, np.sum]})
Out[20]:
mean sum
dummy
1 0.036901 0.369012
or as a dictionary:
In [21]: df.groupby('dummy').agg({'returns':
...
String output: format or concat in C#?
...ded the result by some iterations was wrong. See what happens if you have 1000 milliseconds and 100 milliseconds. In both situations, you will get 0 ms after dividing it by 1000000.
Stopwatch s = new Stopwatch();
var p = new { FirstName = "Bill", LastName = "Gates" };
int n = 1000000;
long fElaps...
Finding local IP addresses using Python's stdlib
How can I find local IP addresses (i.e. 192.168.x.x or 10.0.x.x) in Python platform independently and using only the standard library?
...