大约有 44,000 项符合查询结果（耗时：0.0290秒） [XML]
Principal component analysis in Python
...is 2 x 20. Dropping the primes,
d . Vt 2 principal vars = p.vars_pc( 20 vars )
U 1000 obs = p.pc_obs( 2 principal vars )
U . d . Vt 1000 obs, p.obs( 20 vars ) = pc_obs( vars_pc( vars ))
fast approximate A . vars, using the `npc` principal components
Ut ...
How does functools partial do what it does?
...g like this (apart from keyword args support etc):
def partial(func, *part_args):
def wrapper(*extra_args):
args = list(part_args)
args.extend(extra_args)
return func(*args)
return wrapper
So, by calling partial(sum2, 4) you create a new function (a callable, to b...
What is the “__v” field in Mongoose
I'm using Mongoose version 3 with MongoDB version 2.2. I've noticed a __v field has started appearing in my MongoDB documents. Is it something to do with versioning? How is it used?
...
String concatenation vs. string substitution in Python
...e interpolation/templating.
>>> import timeit
>>> def so_q_sub(n):
... return "%s%s/%d" % (DOMAIN, QUESTIONS, n)
...
>>> so_q_sub(1000)
'http://stackoverflow.com/questions/1000'
>>> def so_q_cat(n):
... return DOMAIN + QUESTIONS + '/' + str(n)
...
>>> ...
How to extract the decision rules from scikit-learn decision-tree?
...wer is more correct than the other answers here:
from sklearn.tree import _tree
def tree_to_code(tree, feature_names):
tree_ = tree.tree_
feature_name = [
feature_names[i] if i != _tree.TREE_UNDEFINED else "undefined!"
for i in tree_.feature
]
print "def tree({}):"....
Best way to require all files from a directory in ruby?
... (e.g. you want to load all files in the lib directory):
Dir[File.dirname(__FILE__) + '/lib/*.rb'].each {|file| require file }
Edit: Based on comments below, an updated version:
Dir[File.join(__dir__, 'lib', '*.rb')].each { |file| require file }
...
How to JSON serialize sets?
I have a Python set that contains objects with __hash__ and __eq__ methods in order to make certain no duplicates are included in the collection.
...
What are the calling conventions for UNIX & Linux system calls (and user-space functions) on i386 an
...rameters for Linux system call are passed using registers. %eax for syscall_number. %ebx, %ecx, %edx, %esi, %edi, %ebp are used for passing 6 parameters to system calls.
The return value is in %eax. All other registers (including EFLAGS) are preserved across the int $0x80.
I took following snipp...
Is there any difference between “foo is None” and “foo == None”?
...pares the same object instance
Whereas == is ultimately determined by the __eq__() method
i.e.
>>> class Foo(object):
def __eq__(self, other):
return True
>>> f = Foo()
>>> f == None
True
>>> f is None
False
...
How to Calculate Execution Time of a Code Snippet in C++
...inux it is implementation dependent, but it usually 15 ms as well.
#ifdef _WIN32
#include <Windows.h>
#else
#include <sys/time.h>
#include <ctime>
#endif
/* Remove if already defined */
typedef long long int64; typedef unsigned long long uint64;
/* Returns the amount of millisec...