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Replace all 0 values to NA
... or cor, that is actually equivalent to first replacing zeroes with NA and setting the value of use as "complete.obs". Typically, however, this is unsatisfactory as it leads to extra information loss.
2. Instead of running some sort of loop, in the solution I use df == 0 vectorization. df == 0 retu...
Is using Random and OrderBy a good shuffle algorithm?
...d/Knuth achieve O(n) not by assignment, but by selection from a decreasing set and swapping. This way the random number selected may repeat and the algorithm only takes O(n).
– tvanfosson
Aug 17 '09 at 12:18
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Alternate output format for psql
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You can also try \pset format wrapped (allowed formats are unaligned, aligned, wrapped, html, latex, troff-ms). If the display is narrow enough it will word wrap each column.
– Bryce
Apr 14 '13 at 23:05
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Create subdomains on the fly with .htaccess (PHP)
...riate data
The long version
1. Create a wildcard DNS entry
In your DNS settings you need to create a wildcard domain entry such as *.example.org. A wildcard entry looks like this:
*.example.org. 3600 A 127.0.0.1
2. Include the wildcard in vhost
Next up in the Apache configuration you nee...
Common programming mistakes for Clojure developers to avoid [closed]
...arper suggests using sequence implementation constructors (array-map, hash-set, vector) like so:
(#(array-map %1 %2) :a 1)
while Dan shows that you can use the identity function to unwrap the outer parenthesis:
(#(identity {%1 %2}) :a 1)
Brian's suggestion actually brings me to my next mistake...
Looking for a clear definition of what a “tokenizer”, “parser” and...
... editor after snippets, if snippets enabled
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Find the files existing in one directory but not in the other [closed]
... bulk copy: +1 from me. (neeed to convert to python2 though) Hint: use of sets might make the diff part simpler.
– Jason Morgan
Referring to the null object in Python
...n addition to False itself, the property is shared by empty lists, tuples, sets, dicts, strings, as well as 0, and all objects from classes that implement the __bool__() magic method to return False.
>>> bool(None)
False
>>> not None
True
>>> bool([])
False
>>> n...
Bitwise operation and usage
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One typical usage:
| is used to set a certain bit to 1
& is used to test or clear a certain bit
Set a bit (where n is the bit number, and 0 is the least significant bit):
unsigned char a |= (1 << n);
Clear a bit:
unsigned char b &= ~(1 &...
Base64: What is the worst possible increase in space usage?
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Base64 encodes each set of three bytes into four bytes. In addition the output is padded to always be a multiple of four.
This means that the size of the base-64 representation of a string of size n is:
ceil(n / 3) * 4
So, for a 16kB array, ...