大约有 15,000 项符合查询结果（耗时：0.0297秒） [XML]
mongodb group values by multiple fields
...tems to $push to an array.
db.books.aggregate([
{ "$group": {
"_id": {
"addr": "$addr",
"book": "$book"
},
"bookCount": { "$sum": 1 }
}},
{ "$group": {
"_id": "$_id.addr",
"books": {
"$push": {
...
In Python, how do I indicate I'm overriding a method?
...an think of a better solution please post it here!
def overrides(interface_class):
def overrider(method):
assert(method.__name__ in dir(interface_class))
return method
return overrider
It works as follows:
class MySuperInterface(object):
def my_method(self):
p...
Is errno thread-safe?
...
@vinit dhatrak There should be # if !defined _LIBC || defined _LIBC_REENTRANT , _LIBC is not defined when compiling normal programs. Anyway, run echo #include <errno.h>' | gcc -E -dM -xc - and look at the difference with and without -pthread. errno is #define er...
how to change any data type into a string in python
... you're writing your own class and you want str to work for you, add:
def __str__(self):
return "Some descriptive string"
print str(myObj) will call myObj.__str__().
repr is a similar method, which generally produces information on the class info. For most core library object, repr produces ...
ImportError in importing from sklearn: cannot import name check_build
...the kernel's socket connection. Fixed by renaming the file multiprocessing_.py (leading underscore did not work).
– pylang
Jan 11 '19 at 2:52
...
Determine the type of an object?
...
On instances of object you also have the:
__class__
attribute. Here is a sample taken from Python 3.3 console
>>> str = "str"
>>> str.__class__
<class 'str'>
>>> i = 2
>>> i.__class__
<class 'int'>
>>> class...
(Mac) -bash: __git_ps1: command not found
...r - in git's development history this is after a commit that split out the __git_ps1 function from the completion functionality into a new file (git-prompt.sh). The commit that introduced this change, which explains the rationale, is af31a456.
I would still suggest that you just source the version...
What's wrong with using $_REQUEST[]?
I've seen a number of posts on here saying not to use the $_REQUEST variable. I usually don't, but sometimes it's convenient. What's wrong with it?
...
Assign a variable inside a Block to a variable outside a Block
...
You need to use this line of code to resolve your problem:
__block Person *aPerson = nil;
For more details, please refer to this tutorial: Blocks and Variables
share
|
improve this...
Can I redirect the stdout in python into some sort of string buffer?
...ngIO import StringIO # Python3 use: from io import StringIO
import sys
old_stdout = sys.stdout
sys.stdout = mystdout = StringIO()
# blah blah lots of code ...
sys.stdout = old_stdout
# examine mystdout.getvalue()
share
...