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Create an index on a huge MySQL production table without table locking
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[2017] Update: MySQL 5.6 has support for online index updates
https://dev.mysql.com/doc/refman/8.0/en/innodb-online-ddl-operations.html#online-ddl-index-syntax-notes
In MySQL 5.6 and higher, the table remains available for...
Associativity of “in” in Python?
... return 1 in [] in 'a'
.....:
In [122]: dis.dis(func)
2 0 LOAD_CONST 1 (1)
3 BUILD_LIST 0
6 DUP_TOP
7 ROT_THREE
8 COMPARE_OP 6 (in)
11 JUMP_IF_FAL...
Numpy how to iterate over columns of array?
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– Ibrahim Muhammad
Sep 23 '13 at 17:08
49
For those wondering, array.T isn't costly, as it just c...
Get loop count inside a Python FOR loop
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605
The pythonic way is to use enumerate:
for idx,item in enumerate(list):
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How to append contents of multiple files into one file
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10 Answers
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How to clear the canvas for redrawing
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const context = canvas.getContext('2d');
context.clearRect(0, 0, canvas.width, canvas.height);
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How to determine CPU and memory consumption from inside a process?
... now;
lastUserCPU = user;
lastSysCPU = sys;
return percent * 100;
}
Linux
On Linux the choice that seemed obvious at first was to use the POSIX APIs like getrusage() etc. I spent some time trying to get this to work, but never got meaningful values. When I finally checked the kern...
Example of Named Pipes
...tring[] args)
{
StartServer();
Task.Delay(1000).Wait();
//Client
var client = new NamedPipeClientStream("PipesOfPiece");
client.Connect();
StreamReader reader = new StreamReader(client);
StreamWriter writer...
Simple way to create matrix of random numbers
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Take a look at numpy.random.rand:
Docstring: rand(d0, d1, ..., dn)
Random values in a given shape.
Create an array of the given shape and propagate it with random
samples from a uniform distribution over [0, 1).
>>> import numpy as np
>>> np....
JavaScript function to add X months to a date
...getMonth() + +months);
if (date.getDate() != d) {
date.setDate(0);
}
return date;
}
// Add 12 months to 29 Feb 2016 -> 28 Feb 2017
console.log(addMonths(new Date(2016,1,29),12).toString());
// Subtract 1 month from 1 Jan 2017 -> 1 Dec 2016
console.log(addMonths(n...