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Remove characters except digits from string using Python?
...ion of "everything but" a few characters:
import string
class Del:
def __init__(self, keep=string.digits):
self.comp = dict((ord(c),c) for c in keep)
def __getitem__(self, k):
return self.comp.get(k)
DD = Del()
x='aaa12333bb445bb54b5b52'
x.translate(DD)
also emits '1233344554552'. ...
Retrieve only the queried element in an object array in MongoDB collection
...atched shapes element:
db.test.find(
{"shapes.color": "red"},
{_id: 0, shapes: {$elemMatch: {color: "red"}}});
Returns:
{"shapes" : [{"shape": "circle", "color": "red"}]}
In 2.2 you can also do this using the $ projection operator, where the $ in a projection object field name repre...
Iterate keys in a C++ map
...te on the keys instead of the pairs), then take a look at Boost's transform_iterator.
[Tip: when looking at Boost documentation for a new class, read the "examples" at the end first. You then have a sporting chance of figuring out what on earth the rest of it is talking about :-)]
...
What is the difference between typeof and instanceof and when should one be used vs. the other?
...ot work as expected and typeof works well ... developer.mozilla.org/En/Core_JavaScript_1.5_Reference/…
– farinspace
May 22 '09 at 19:37
55
...
“Inner exception” (with traceback) in Python?
...peError("test")
except TypeError, e:
raise MyException(), None, sys.exc_info()[2]
Always do this when catching one exception and re-raising another.
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pandas three-way joining multiple dataframes on columns
...ve some common column, like name in your example, I'd do the following:
df_final = reduce(lambda left,right: pd.merge(left,right,on='name'), dfs)
That way, your code should work with whatever number of dataframes you want to merge.
Edit August 1, 2016: For those using Python 3: reduce has been m...
Python's many ways of string formatting — are the older ones (going to be) deprecated?
...0}".format(world, greeting='Hello')
and is extensible through the object.__format__() hook used to handle formatting of individual values.
Note that the old system had % and the Template class, where the latter allows you to create subclasses that add or alter its behaviour. The new-style system ...
ImportError: No module named pip
...
After installing ez_setup, you should have easy_install available. To install pip just do:
easy_install pip
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Get local IP address
... edited Oct 17 '17 at 19:32
ivan_pozdeev
26.5k1010 gold badges7676 silver badges124124 bronze badges
answered Jul 23 '11 at 20:26
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How to get the directory of the currently running file?
In nodejs I use __dirname . What is the equivalent of this in Golang?
10 Answers
10
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