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Seeding the random number generator in Javascript
...oose some dummy data to pad the seed with, and advance the generator a few times (12-20 iterations) to mix the initial state thoroughly. This is often seen in reference implementations of PRNGs, but it does limit the number of initial states.
var seed = 1337 ^ 0xDEADBEEF; // 32-bit seed with option...
How to create an alias for a command in Vim?
... This is the single best tip for vim. I'm so used to it now that every time I encounter the normal behavior, it takes me a few tried to get my mind retrained.
– airstrike
Feb 24 '15 at 19:58
...
Why do we copy then move?
...ion gets us nearly the same performance as the most-optimal version, but 2 times less code.
And if you are taking say 2 to 10 arguments, the reduction in code is exponential -- 2x times less with 1 argument, 4x with 2, 8x with 3, 16x with 4, 1024x with 10 arguments.
Now, we can get around this via...
Reading a file line by line in Go
... in bufio.Reader
In my testcase, ~250MB, ~2,500,000 lines, bufio.Scanner(time used: 0.395491384s) is faster than bufio.Reader.ReadString(time_used: 0.446867622s).
Source code: https://github.com/xpzouying/go-practice/tree/master/read_file_line_by_line
Read file use bufio.Scanner,
func scanFile(...
What are some (concrete) use-cases for metaclasses?
...hrough all the class attributes and all its base classes' attributes every time):
>>> class A(Model):
... foo = Integer()
...
>>> class B(A):
... bar = String()
...
>>> B._fields
{'foo': Integer('A.foo'), 'bar': String('B.bar')}
Again, this can be done (without ...
str performance in python
...100000 is evaluated by the compiler and is equivalent to a constant at run-time.
>>> import dis
>>> dis.dis(lambda: str(100000))
8 0 LOAD_GLOBAL 0 (str)
3 LOAD_CONST 1 (100000)
6 CALL_FUNCTION 1
...
Rename specific column(s) in pandas
... name
df.columns = [col_dict.get(x, x) for x in df.columns]
Timings:
%%timeit
df.rename(columns={'gdp':'log(gdp)'}, inplace=True)
10000 loops, best of 3: 168 µs per loop
%%timeit
df.columns = ['log(gdp)' if x=='gdp' else x for x in df.columns]
10000 loops, best of 3: 58.5 µs per loop
...
How can I check if a URL exists via PHP?
...ax), this is quick to check server side.
Waiting for a response might take time and block code execution.
Not all headers returned by get_headers() are well formed.
Use curl (if you can).
Prevent fetching the entire body/content, but only request the headers.
Consider redirecting urls:
Do you want t...
Variable declared in for-loop is local variable?
I have been using C# for quite a long time but never realised the following:
9 Answers
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How do you find the row count for all your tables in Postgres
... count for all my tables in Postgres. I know I can do this one table at a time with:
15 Answers
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