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Intersection of two lists in Bash
... comm requires the inputs to be sorted. In this case, ls automatically sorts its output, but other uses may need to do this: comm -12 <(some-command | sort) <(some-other-command | sort)
– Alexander Bird
Jan 15 '15 at 21:11
...
How to check if a python module exists without importing it
...ING
When trying to find a submodule, it will import the parent module (for all of the above methods)!
food/
|- __init__.py
|- eggs.py
## __init__.py
print("module food loaded")
## eggs.py
print("module eggs")
were you then to run
>>> import importlib
>>> spam_spec = importli...
Multi-line string with extra space (preserved indentation)
...sh documentation it doesn't seem to say anything one way or the other, but all the examples have it on its own line.
– Andrew Miner
Jan 18 '17 at 16:08
...
No ConcurrentList in .Net 4.0?
...read-safe, limited subset of IList<T>: in particular, one that would allow an Add and provide random read-only access by index (but no Insert, RemoveAt, etc., and also no random write access).
This was the goal of my ConcurrentList<T> implementation. But when I tested its performance in...
What is the difference between join and merge in Pandas?
...
pandas.merge() is the underlying function used for all merge/join behavior.
DataFrames provide the pandas.DataFrame.merge() and pandas.DataFrame.join() methods as a convenient way to access the capabilities of pandas.merge(). For example, df1.merge(right=df2, ...) is equiva...
Python Empty Generator Function
... list(f())
[None]
Why not just use iter(())?
This question asks specifically about an empty generator function. For that reason, I take it to be a question about the internal consistency of Python's syntax, rather than a question about the best way to create an empty iterator in general.
If ques...
How can I rename a field for all documents in MongoDB?
...above are: { upsert:false, multi:true }. You need the multi:true to update all your records.
Or you can use the former way:
remap = function (x) {
if (x.additional){
db.foo.update({_id:x._id}, {$set:{"name.last":x.name.additional}, $unset:{"name.additional":1}});
}
}
db.foo.find().forEach...
Does the C++ standard mandate poor performance for iostreams, or am I just dealing with a poor imple
...f the work can
be avoided. With a slightly smarter
linker than is typically used, it is
possible to remove some of these
inefficiencies. This is discussed in
§6.2.3 and §6.2.5.
Since the report was written in 2006 one would hope that many of the recommendations would have been incorpor...
领域驱动设计系列（三）:事件驱动上 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...ce emailService, IEquipmentRepository equipmentRepository)
{
_emailService = emailService;
_equipmentRepository = equipmentRepository;
}
为何用事件？
SRP （单一职责)
比如我们一个会议室预定系统，我们的一个设备坏了。我们需要通知...
【phpcms v9】html静态化设置及URL规则优化 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...成：
{$categorydir}{$catdir}/index.html|{$categorydir}{$catdir}/index_{$page}.html
按照栏目index页面生成，栏目列表变成：index.html、index_2.html、index_3.html……这样比较明朗。
如果要自定义生成到某一个固定的目录，可以在前面添加一个特...