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hash function for string
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@Josepas the hash function should ideally return a size_t or other such unsigned value (such as the unsigned long in this code). The caller is responsible for taking modulo of the result to fit it to the hash table. The caller controls the table slot being hashed to; not the func...
Troubleshooting “Illegal mix of collations” error in mysql
...ERE clause will always give the error you posted:
WHERE 'A' COLLATE latin1_general_ci = 'A' COLLATE latin1_general_cs
Your solution is to specify a shared collation for the two columns within the query. Here is an example that uses the COLLATE clause:
SELECT * FROM table ORDER BY key COLLATE lat...
mongodb: insert if not exists
... This is almost what I want ! How can I not touch the insertion_date field if the object is already present ?
– LeMiz
May 27 '10 at 21:24
28
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Calling shell functions with xargs
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Exporting the function should do it (untested):
export -f echo_var
seq -f "n%04g" 1 100 | xargs -n 1 -P 10 -I {} bash -c 'echo_var "$@"' _ {}
You can use the builtin printf instead of the external seq:
printf "n%04g\n" {1..100} | xargs -n 1 -P 10 -I {} bash -c 'echo_var "$@"' _ {}
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Storing time-series data, relational or non?
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Create a file, name it 1_2.data. weired idea? what you get:
You save up to 50% of space because you don't need to repeat the fk_to_device and fk_to_metric value for every data point.
You save up even more space because you don't need any indices.
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trying to animate a constraint in swift
...t tapGesture = UITapGestureRecognizer(target: self, action: #selector(doIt(_:)))
textView.addGestureRecognizer(tapGesture)
}
@objc func doIt(_ sender: UITapGestureRecognizer) {
heightConstraint.constant = heightConstraint.constant == 50 ? 150 : 50
UIView.animate(with...
What is Scala's yield?
...I use yield instead of map? This map code is equivalent val res = args.map(_.toUpperCase) , right?
– Geo
Jun 27 '09 at 12:23
4
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Getting a random value from a JavaScript array
...u've already got underscore or lodash included in your project you can use _.sample.
// will return one item randomly from the array
_.sample(['January', 'February', 'March']);
If you need to get more than one item randomly, you can pass that as a second argument in underscore:
// will return tw...
How to open, read, and write from serial port in C?
...;string.h>
#include <termios.h>
#include <unistd.h>
int
set_interface_attribs (int fd, int speed, int parity)
{
struct termios tty;
if (tcgetattr (fd, &tty) != 0)
{
error_message ("error %d from tcgetattr", errno);
return -1...
Turn off Visual Studio Attach security warning when debugging IIS
...hange (or create) the following registry key to 1:
Visual Studio 2008 HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0\Debugger\DisableAttachSecurityWarning
Visual Studio 2010 HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\10.0\Debugger\DisableAttachSecurityWarning
Visual Studio 2012
HKEY...