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Insert into … values ( SELECT … FROM … )
...SERT from another table I did the following in SQLite3:
INSERT INTO column_1 ( val_1, val_from_other_table )
VALUES('val_1', (SELECT val_2 FROM table_2 WHERE val_2 = something))
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Sleep for milliseconds
... facilities:
#include <chrono>
#include <thread>
std::this_thread::sleep_for(std::chrono::milliseconds(x));
Clear and readable, no more need to guess at what units the sleep() function takes.
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select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
...1、select实现
select的调用过程如下所示：
（1）使用copy_from_user从用户空间拷贝fd_set到内核空间
（2）注册回调函数__pollwait
（3）遍历所有fd，调用其对应的poll方法（对于socket，这个poll方法是sock_poll，sock_poll根据情况会调用到...
How to mark a class as Deprecated? [duplicate]
...licy (e.g., maintenance and existence of the classes until version X.X) in order to allow them to plan a proper migration to your new API.
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How to export table as CSV with headings on Postgresql?
...
COPY products_273 TO '/tmp/products_199.csv' WITH (FORMAT CSV, HEADER);
as described in the manual.
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How do I access command line arguments in Python?
...a small example:
import argparse
parser = argparse.ArgumentParser("simple_example")
parser.add_argument("counter", help="An integer will be increased by 1 and printed.", type=int)
args = parser.parse_args()
print(args.counter + 1)
and the output for python prog.py -h
usage: simple_example [-h] ...
When do items in HTML5 local storage expire?
... localStorage.removeItem(name);
localStorage.removeItem(name + '_expiresIn');
} catch(e) {
console.log('removeStorage: Error removing key ['+ key + '] from localStorage: ' + JSON.stringify(e) );
return false;
}
return true;
}
/* getStorage: retrieves a key fro...
How to format a floating number to fixed width in Python
... may be useful is when you want to properly list filenames in alphabetical order. I noticed in some linux systems, the number is: 1,10,11,..2,20,21,...
Thus if you want to enforce the necessary numeric order in filenames, you need to left pad with the appropriate number of zeros.
...
How to pass variable from jade template file to a script file?
...s how I addressed this (using a MEAN derivative)
My variables:
{
NODE_ENV : development,
...
ui_varables {
var1: one,
var2: two
}
}
First I had to make sure that the necessary config variables were being passed. MEAN uses the node nconf package, and by default is set up to li...
How can I strip first X characters from string using sed?
...aces are used to concatenate the string with valid variable characters, in order to distinguish what is the variable and what isn't. If you want more information on this, then look up "bash variable string concatenation" for more resources on why / how this works.
– JustCarty
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