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...rticle. Pythons hashing algorithms are explained on effbot.org and pythons __hash__ function in the python reference.
Some facts:
Set elements as well as dictionary keys have to be hashable
Some unhashable datatypes:
list: use tuple instead
set: use frozenset instead
dict: has no official count...
SQL - Rounding off to 2 decimal places
...the round v cast on its own. The convert to numeric doesn't do rounding in all engines so if the calculated number was 10.809 you would get 10.80 rather than the 10.81 the question required.
– u07ch
Aug 26 '14 at 7:47
...
How to print the full NumPy array, without truncation?
...ld instead of a.size <= _summaryThreshold, and np.nan returns False for all >/</>=/<= comparisons. 'nan' only happens to work due to fragile implementation details of Python 2's mixed-type comparison logic; it breaks completely on Python 3.
– user2357112 supports...
How can I remove the string “\n” from within a Ruby string?
... your gsub. The different quote marks behave differently.
Double quotes " allow character expansion and expression interpolation ie. they let you use escaped control chars like \n to represent their true value, in this case, newline, and allow the use of #{expression} so you can weave variables and...
Why doesn't 'ref' and 'out' support polymorphism?
...nswer as the basis for this blog entry:
Why do ref and out parameters not allow type variation?
See the blog page for more commentary on this issue. Thanks for the great question.
=============
Let's suppose you have classes Animal, Mammal, Reptile, Giraffe, Turtle and Tiger, with the obvious s...
Checking if a string array contains a value, and if so, getting its position
...
You could use the Array.IndexOf method:
string[] stringArray = { "text1", "text2", "text3", "text4" };
string value = "text3";
int pos = Array.IndexOf(stringArray, value);
if (pos > -1)
{
// the array contains the string and the pos variable
...
Select random row from a sqlite table
... the day seeded with unix epoc for today at noon so it shows the same book all day even if the query is run multiple times. Yes I know caching is more efficient for this use case just an example.
– danielson317
Apr 22 at 17:18
...
What is Double Brace initialization in Java?
...as an implicit this pointer to the surrounding outer class. Whilst not normally a problem, it can cause grief in some circumstances e.g. when serialising or garbage collecting, and it's worth being aware of this.
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NodeJS / Express: what is “app.use”?
...gt;) for every middleware layer that you want to add (it can be generic to all paths, or triggered only on specific path(s) your server handles), and it will add onto your Express middleware stack. Middleware layers can be added one by one in multiple invocations of use, or even all at once in seri...
Quickly create a large file on a Linux system
... it is slow for this purpose. In Linux (and other POSIX systems), we have fallocate, which uses the desired space without having to actually writing to it, works with most modern disk based file systems, very fast:
For example:
fallocate -l 10G gentoo_root.img
...