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Specifying rails version to use when creating a new application
I have two versions of rails (2.1.0 and 2.2.2) installed in my computer.
7 Answers
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Calculate difference in keys contained in two Python dictionaries
...s:
diff = set(dictb.keys()) - set(dicta.keys())
Here is a class to find all the possibilities: what was added, what was removed, which key-value pairs are the same, and which key-value pairs are changed.
class DictDiffer(object):
"""
Calculate the difference between two dictionaries as:
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Why does changing 0.1f to 0 slow down performance by 10x?
...ond run the numbers are very close to zero.
Denormalized numbers are generally rare and thus most processors don't try to handle them efficiently.
To demonstrate that this has everything to do with denormalized numbers, if we flush denormals to zero by adding this to the start of the code:
_MM_...
What are the differences between NP, NP-Complete and NP-Hard?
... the technical definitions require quite some time to understand. First of all, let's remember a preliminary needed concept to understand those definitions.
Decision problem: A problem with a yes or no answer.
Now, let us define those complexity classes.
P
P is a complexity class that repres...
ViewPager and fragments — what's the right way to store fragment's state?
...agment will be placed. FragmentPagerAdapter.getItem(int position) is only called when a fragment for that position does not exist. After rotating, Android will notice that it already created/saved a fragment for this particular position and so it simply tries to reconnect with it with FragmentManage...
Find MongoDB records where array field is not empty
All of my records have a field called "pictures". This field is an array of strings.
11 Answers
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Detecting endianness programmatically in a C++ program
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Is this solution really portable? What if CHAR_BIT != 8 ?
– zorgit
May 30 '15 at 20:12
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Recursive sub folder search and return files in a list python
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You should be using the dirpath which you call root. The dirnames are supplied so you can prune it if there are folders that you don't wish os.walk to recurse into.
import os
result = [os.path.join(dp, f) for dp, dn, filenames in os.walk(PATH) for f in filenames if o...
Naming returned columns in Pandas aggregate function? [duplicate]
...er, this does not work with lambda functions, since they are anonymous and all return <lambda>, which causes a name collision:
>>> df.groupby('A').agg({'B': [lambda x: x.min(), lambda x: x.max]})
SpecificationError: Function names must be unique, found multiple named <lambda>
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Multi-statement Table Valued Function vs Inline Table Valued Function
...e compiler cannot use any table statistics on the tables in the MSTVF. So, all things being equal, (which they rarely are), the ITVF will perform better than the MSTVF. In my tests, the performance difference in completion time was negligible however from a statistics standpoint, it was noticeable.
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