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Which is the preferred way to concatenate a string in Python?
...esulting string is a million characters long, appending was still faster.
Now let's try with appending a thousand character long string a hundred thousand times:
a += b:
0.41823482513427734
a.append(b):
0.010656118392944336
The end string, therefore, ends up being about 100MB long. That was pret...
Where is the C auto keyword used?
...
If you'd read the IAQ (Infrequently Asked Questions) list, you'd know that auto is useful primarily to define or declare a vehicle:
auto my_car;
A vehicle that's consistently parked outdoors:
extern auto my_car;
For those who lack any sense of humor and want "just the facts Ma'am": th...
Get records with max value for each group of grouped SQL results
...wers would do)
Note: This is a mysql-only solution. All other databases I know will throw an SQL syntax error with the message "non aggregated columns are not listed in the group by clause" or similar. Because this solution uses undocumented behavior, the more cautious may want to include a test to ...
Is there a C# type for representing an integer Range?
...
Ranges and Indices are released with C#8.0 and .NET Core.
You are now able to do
string[] names =
{
"Archimedes", "Pythagoras", "Euclid", "Socrates", "Plato"
};
foreach (var name in names[1..4])
{
yield return name;
}
Check out https://blogs.msdn.microsoft.com/dotnet/2018/12/05/tak...
CSS: how do I create a gap between rows in a table?
...separate, not border collapse, using the border separation to define, you know, the border separation.
– John Haugeland
May 29 '13 at 17:08
...
Linux: copy and create destination dir if it does not exist
... might have a shell that doesn't support this construct. However, I don't know of any modern shells that don't support $_; certainly Bash, Dash, and zsh all do.
A final note: the command I've given at the start of this answer assumes that your directory names don't have spaces in. If you're deali...
How to change the playing speed of videos in HTML5?
...o').defaultPlaybackRate = 2.0;
document.querySelector('video').play();
/* now play three times as fast just for the heck of it */
document.querySelector('video').playbackRate = 3.0;
The above works on Chrome 43+, Firefox 20+, IE 9+, Edge 12+.
...
Setting a timeout for socket operations
...xception (but not increase it), and it has no effect on the timeout for UnknownHostException, which the OP claims he is getting (although I don't believe it). Note also that the Javadoc is incorrect in stating that the default is infinity. It isn't. The platform has a default timeout of around a min...
How to match a String against string literals in Rust?
...
as_slice is deprecated, you should now use the trait std::convert::AsRef instead:
match stringthing.as_ref() {
"a" => println!("0"),
"b" => println!("1"),
"c" => println!("2"),
_ => println!("something else!"),
}
Note that you al...
MySql Table Insert if not exist otherwise update
...
now I defined the datenum as unique, and it's work fine, thanks
– OHLÁLÁ
May 18 '11 at 8:21
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