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Scala how can I count the number of occurrences in a list
...", "banana", "apple", "oranges", "oranges")
s.groupBy(identity).mapValues(_.size)
giving a Map with a count for each item in the original sequence:
Map(banana -> 1, oranges -> 3, apple -> 3)
The question asks how to find the count of a specific item. With this approach, the solution w...
Retain cycle on `self` with blocks
...sue is identical to the workaround for the retain issue; namely, using the __block storage class for the variable.
In any case, to answer your question, there's no real alternative here. If you're designing your own block-based API, and it makes sense to do so, you could have the block get passed t...
How can I get all the request headers in Django?
...m HTTP headers.
From the documentation:
With the exception of CONTENT_LENGTH and CONTENT_TYPE, as given above, any HTTP headers in the request are converted to META keys by converting all characters to uppercase, replacing any hyphens with underscores and adding an HTTP_ prefix to the name.
...
Multiple INSERT statements vs. single INSERT with multiple VALUES
...ried a query consisting entirely of duplicate rows and neither affects the order of the output of the table of the constants (and as you are inserting into a heap time spent sorting would be pointless anyway even if it did).
Moreover if a clustered index is added to the table the plan still shows ...
Python argparse: Make at least one argument required
...
args = vars(parser.parse_args())
if not any(args.values()):
parser.error('No arguments provided.')
share
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improve this answer
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What is the difference between “INNER JOIN” and “OUTER JOIN”?
...great and excellent explanation. but why in column b the values are not in order? i.e it is 6,5 not as 5,6?
– Ameer
Mar 4 '13 at 8:39
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What is a elegant way in Ruby to tell if a variable is a Hash or an Array?
...
This won't work if your code is dependent on the ordering of the data(e.g. if you are using each_with_index). The order of the elements is implemented differently between hashes and arrays and it is different between ruby versions.(intertwingly.net/slides/2008/oscon/ruby19/...
Python division
...t:
>>> float(10 - 20) / (100 - 10)
-0.1111111111111111
or from __future__ import division, which the forces / to adopt Python 3.x's behavior that always returns a float.
>>> from __future__ import division
>>> (10 - 20) / (100 - 10)
-0.1111111111111111
...
How to iterate through two lists in parallel?
... And to zip until both iterators are
exhausted, you would use
itertools.zip_longest.
Python 2
In Python 2, zip
returns a list of tuples. This is fine when foo and bar are not massive. If they are both massive then forming zip(foo,bar) is an unnecessarily massive
temporary variable, and should be r...
How can I mock requests and the response?
...mock
# This is the class we want to test
class MyGreatClass:
def fetch_json(self, url):
response = requests.get(url)
return response.json()
# This method will be used by the mock to replace requests.get
def mocked_requests_get(*args, **kwargs):
class MockResponse:
d...