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Does MongoDB's $in clause guarantee order
...course will be the natural order or by the selected index order as shown.
If you need to preserve this order, then you basically have two options.
So let's say that you were matching on the values of _id in your documents with an array that is going to be passed in to the $in as [ 4, 2, 8 ].
Appr...
How to use putExtra() and getExtra() for string data
...Actually I have a string variable, say str, which stores some string data. Now, I want to send this data from one activity to another activity.
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Adding a directory to $LOAD_PATH (Ruby)
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I would say go with $:.unshift File.dirname(__FILE__) over the other one, simply because I've seen much more usage of it in code than the $LOAD_PATH one, and it's shorter too!
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How do I create a constant in Python?
...t declare a variable or value as constant in Python. Just don't change it.
If you are in a class, the equivalent would be:
class Foo(object):
CONST_NAME = "Name"
if not, it is just
CONST_NAME = "Name"
But you might want to have a look at the code snippet Constants in Python by Alex Martelli.
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How to pass a user defined argument in scrapy spider
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The above code is only partially working for me. For eg. If I define domain using self.domain, I'm still not able to access it outside the __init__ method. Python throws a not defined error. BTW, why have you omitted the super call? PS. I'm working with the CrawlSpider class
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Empty set literal?
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By all means, please use set() to create an empty set.
But, if you want to impress people, tell them that you can create an empty set using literals and * with Python >= 3.5 (see PEP 448) by doing:
>>> s = {*()} # or {*{}} or {*[]}
>>> print(s)
set()
this is b...
MongoDB数据导出导入工具：mongoexport,mongoimport - 大数据 & AI - 清泛...
...to lock the data directory, so cannot be used
if a mongod is currently accessing the same path
--directoryperdb if dbpath specified, each db is in a separate
directory
--journal enable journaling
-d [ --db ] ...
How to correctly implement custom iterators and const_iterators?
...rs, we derive from the standard iterator categories to let STL algorithms know the type of iterator we've made.
In this example, I define a random access iterator and a reverse random access iterator:
//-------------------------------------------------------------------
// Raw iterator with rando...
Stop pip from failing on single package when installing with requirements.txt
...out the -a flag, consider < requirements.txt xargs -n 1 pip install, or if you don't like the redirect at the front, xargs -n 1 pip install < requirements.txt. :-)
– torek
Jul 6 at 17:21
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How to manage local vs production settings in Django?
...sed in both, but some of them (like paths to static files) need to remain different, and hence should not be overwritten every time the new code is deployed.
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