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String concatenation: concat() vs “+” operator
...then throwing it away when you create the final String. In practice memory allocation is surprisingly fast.
Update: As Pawel Adamski notes, performance has changed in more recent HotSpot. javac still produces exactly the same code, but the bytecode compiler cheats. Simple testing entirely fails bec...
How do you convert an entire directory with ffmpeg?
...
And on Windows:
FOR /F "tokens=*" %G IN ('dir /b *.flac') DO ffmpeg -i "%G" -acodec mp3 "%~nG.mp3"
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parsing JSONP $http.jsonp() response in angular.js
...You still need to set callback in the params:
var params = {
'a': b,
'token_auth': TOKEN,
'callback': 'functionName'
};
$sce.trustAsResourceUrl(url);
$http.jsonp(url, {
params: params
});
Where 'functionName' is a stringified reference to globally defined function. You can define it outs...
Determine the number of lines within a text file
...ne loads the entire contents of the file into an array which means it must allocate at least as much memory as the size of the file. The second merely loops one line at a time so it never has to allocate more than one line's worth of memory at a time. This isn't that important for small files, but f...
Python Write bytes to file
...turns a string. The string contains carriage returns and new line feeds (0x0D, 0x0A). However when I write to a file it contains only the new line feeds. Is there a way to get the output to include the carriage return and the new line feed.
...
How to port data-only volumes from one host to another?
...-server on a machine you want to copy data from (You'll need the NGROK_AUTHTOKEN which can be obtained from ngrok dashboard):
$ docker run --rm -e NGROK_AUTHTOKEN="$NGROK_AUTHTOKEN" \
--mount source=MY_VOLUME,target=/data,readonly \
quay.io/suda/dvsync-server
Then you can start the dvsync-cli...
Explain the concept of a stack frame in a nutshell
...rocessor knows anything about stack, because WE manipulate it via subbing (allocation), pushing and popping. And so here are calling conventions which explain how we should use the stack.
– Victor Polevoy
Apr 18 '18 at 7:18
...
What is base 64 encoding used for?
...e data bloats three-fold.
Hexadecimal: store the bytes as hex pairs: AC 47 0D 1A etc. where each byte is represented by 2 bytes. The data bloats two-fold.
Base-64 maps 3 bytes (8 x 3 = 24 bits) in 4 characters that span 6-bits (6 x 4 = 24 bits). The result looks something like "TWFuIGlzIGRpc3Rpb.....
What does the “__block” keyword mean?
...and static.[testme] Variables qualified by __block act as if they were in allocated storage and this storage is automatically recovered after last use of said variable. An implementation may choose an optimization where the storage is initially automatic and only "moved" to allocated (heap) storag...
What do the plus and minus signs mean in Objective-C next to a method?
...se?
[CustomClass classMethod];
CustomClass *classObject = [[CustomClass alloc] init];
[classObject instanceMethod];
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