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Python: Append item to list N times
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For immutable data types:
l = [0] * 100
# [0, 0, 0, 0, 0, ...]
l = ['foo'] * 100
# ['foo', 'foo', 'foo', 'foo', ...]
For values that are stored by reference and you may wish to modify later (like sub-lists, or dicts):
l = [{} for x in range(100)]
(Th...
Scala type programming resources
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+50
Overview
Type-level programming has many similarities with traditional, value-level programming. However, unlike value-level programm...
COUNT DISTINCT with CONDITIONS
...count(distinct tag) as tag_count,
count(distinct (case when entryId > 0 then tag end)) as positive_tag_count
from
your_table_name;
The first count(distinct...) is easy.
The second one, looks somewhat complex, is actually the same as the first one, except that you use case...when clause. In ...
How to Rotate a UIImage 90 degrees?
...rientationUp (portrait) that I would like to rotate counter-clockwise by 90 degrees (to landscape). I don't want to use a CGAffineTransform . I want the pixels of the UIImage to actually shift position. I am using a block of code (shown below) originally intended to resize a UIImage to do this...
Checking if array is multidimensional or not?
...anywhere. If it has to be in the first item, you'd just do
is_array($arr[0]);
But, the most efficient general way I could find is to use a foreach loop on the array, shortcircuiting whenever a hit is found (at least the implicit loop is better than the straight for()):
$ more multi.php
<?php...
Format output string, right alignment
...r.format syntax:
line_new = '{:>12} {:>12} {:>12}'.format(word[0], word[1], word[2])
And here's how to do it using the old % syntax (useful for older versions of Python that don't support str.format):
line_new = '%12s %12s %12s' % (word[0], word[1], word[2])
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do { … } while (0) — what is it good for? [duplicate]
I've been seeing that expression for over 10 years now. I've been trying to think what it's good for. Since I see it mostly in #defines, I assume it's good for inner scope variable declaration and for using breaks (instead of gotos.)
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how to check redis instance version?
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310
$ redis-server --version
gives you the version.
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How to use shared memory with Linux in C
...lains their purpose.
return mmap(NULL, size, protection, visibility, -1, 0);
}
The following is an example program that uses the function defined above to allocate a buffer. The parent process will write a message, fork, and then wait for its child to modify the buffer. Both processes can read a...
How to run cron job every 2 hours
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Just do:
0 */2 * * * /home/username/test.sh
The 0 at the beginning means to run at the 0th minute. (If it were an *, the script would run every minute during every second hour.)
Don't forget, you can check syslog to see if it eve...