大约有 45,000 项符合查询结果（耗时：0.0536秒） [XML]
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.
...
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 pass a user defined argument in scrapy spider
...
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
...
Adding a directory to $LOAD_PATH (Ruby)
...
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!
...
How do I extend a class with c# extension methods?
...
{
public static DateTime Tomorrow
{
get { return DateTime.Now.AddDays(1); }
}
}
Which you would use like this:
DateTime tomorrow = DateTimeHelper.Tomorrow;
share
|
improve t...
Get exception description and stack trace which caused an exception, all as a string
...
See the traceback module, specifically the format_exc() function. Here.
import traceback
try:
raise ValueError
except ValueError:
tb = traceback.format_exc()
else:
tb = "No error"
finally:
print tb
...
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 ] ...
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
...
Lua简明教程 - 脚本技术 - 清泛IT论坛，有思想、有深度
...m
num = num + 1
end
print("sum =",sum)复制代码
if-else分支
if age == 40 and sex =="Male" then
print("男人四十一枝花")
elseif age > 60 and sex ~="Female" then
print("old man without country!")
...
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.
...