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How to print third column to last column?
... Note that this only works if the delimiter is exactly the same between all columns... For example, you can't use cut with a delimiter like \d+. (That I know of.)
– Zach Wily
Jan 13 '10 at 21:11
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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...
Can I query MongoDB ObjectId by date?
...Seconds + "0000000000000000");
return constructedObjectId
}
/* Find all documents created after midnight on May 25th, 1980 */
db.mycollection.find({ _id: { $gt: objectIdWithTimestamp('1980/05/25') } });
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Reverse / invert a dictionary mapping
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For Python 2.7.x
inv_map = {v: k for k, v in my_map.iteritems()}
For Python 3+:
inv_map = {v: k for k, v in my_map.items()}
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Dynamically replace the contents of a C# method?
What I want to do is change how a C# method executes when it is called, so that I can write something like this:
9 Answers
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Factory pattern in C#: How to ensure an object instance can only be created by a factory class?
...some check before creating an object, probably in its constructor. This is all okay until I decide I want to make this check be a part of the business logic. So, how can I arrange for a business object to be creatable only through some method in my business logic class but never directly? The first ...
How do I add a new sourceset to Gradle?
...nk it up? I also find this exact situation severely lacking in docs: It is all well and good defining a new sourceSet, but no info about "hooking this into" the actual compile, jar, test and whatnot targets - as this example does (except for adding into the jar, or making a new jar, out of that sour...
Improve INSERT-per-second performance of SQLite
...more memory will be used for your database.
If you have indices, consider calling CREATE INDEX after doing all your inserts. This is significantly faster than creating the index and then doing your inserts.
You have to be quite careful if you have concurrent access to SQLite, as the whole database i...
filter for complete cases in data.frame using dplyr (case-wise deletion)
...data.frame for complete cases using dplyr? complete.cases with a list of all variables works, of course. But that is a) verbose when there are a lot of variables and b) impossible when the variable names are not known (e.g. in a function that processes any data.frame).
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python pandas: apply a function with arguments to a series
...to pass extra arguments (see the new documentation). So now you can do:
my_series.apply(your_function, args=(2,3,4), extra_kw=1)
The positional arguments are added after the element of the series.
For older version of pandas:
The documentation explains this clearly. The apply method accepts a...