大约有 40,000 项符合查询结果（耗时：0.0454秒） [XML]
Function for Factorial in Python
...The concept used here is called recursion ( en.wikipedia.org/wiki/Recursion_(computer_science) ) - a function calling itself is perfectly fine and often useful.
– schnaader
Nov 7 '14 at 10:06
...
Sort hash by key, return hash in Ruby
...
In Ruby 2.1 it is simple:
h.sort.to_h
share
|
improve this answer
|
follow
|
...
C++ Dynamic Shared Library on Linux
...
myclass.h
#ifndef __MYCLASS_H__
#define __MYCLASS_H__
class MyClass
{
public:
MyClass();
/* use virtual otherwise linker will try to perform static linkage */
virtual void DoSomething();
private:
int x;
};
#endif
myclass.cc
#inc...
How to convert Strings to and from UTF8 byte arrays in Java
...]:
String s = "some text here";
byte[] b = s.getBytes(StandardCharsets.UTF_8);
Convert from byte[] to String:
byte[] b = {(byte) 99, (byte)97, (byte)116};
String s = new String(b, StandardCharsets.US_ASCII);
You should, of course, use the correct encoding name. My examples used US-ASCII and UT...
TypeError: 'NoneType' object is not iterable in Python
...r a variable containing None. The operation was performed by invoking the __iter__ method on the None.
None has no __iter__ method defined, so Python's virtual machine tells you what it sees: that NoneType has no __iter__ method.
This is why Python's duck-typing ideology is considered bad. The...
Python json.loads shows ValueError: Extra data
...le "<stdin>", line 1, in <module>
File "C:\Python27\lib\json\__init__.py", line 338, in loads
return _default_decoder.decode(s)
File "C:\Python27\lib\json\decoder.py", line 368, in decode
raise ValueError(errmsg("Extra data", s, end, len(s)))
ValueError: Extra data: line 1 co...
Convert Python dictionary to JSON array
...
If you are fine with non-printable symbols in your json, then add ensure_ascii=False to dumps call.
>>> json.dumps(your_data, ensure_ascii=False)
If ensure_ascii is false, then the return value will be a
unicode instance subject to normal Python str to unicode
coercion rules in...
Memoization in Haskell?
...alling, for example: fix f 123 = 144
We could memoize this by defining:
f_list :: [Int]
f_list = map (f faster_f) [0..]
faster_f :: Int -> Int
faster_f n = f_list !! n
That performs passably well, and replaces what was going to take O(n^3) time with something that memoizes the intermediate r...
Can Powershell Run Commands in Parallel?
...
# Execute the jobs in parallel
Start-Job $ScriptBlock -ArgumentList $_
}
Get-Job
# Wait for it all to complete
While (Get-Job -State "Running")
{
Start-Sleep 10
}
# Getting the information back from the jobs
Get-Job | Receive-Job
...
Plot two histograms on single chart with matplotlib
...dom
import numpy
from matplotlib import pyplot
x = [random.gauss(3,1) for _ in range(400)]
y = [random.gauss(4,2) for _ in range(400)]
bins = numpy.linspace(-10, 10, 100)
pyplot.hist(x, bins, alpha=0.5, label='x')
pyplot.hist(y, bins, alpha=0.5, label='y')
pyplot.legend(loc='upper right')
pyplot....