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Find the most common element in a list
...for an item
def _auxfun(g):
item, iterable = g
count = 0
min_index = len(L)
for _, where in iterable:
count += 1
min_index = min(min_index, where)
# print 'item %r, count %r, minind %r' % (item, count, min_index)
return count, -min_index
# pick the highest-cou...
How do I overload the square-bracket operator in C#?
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This isn't operator overloading. It is indexer
– Destructor
May 12 '16 at 8:32
5
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How to select rows that have current day's timestamp?
...table` WHERE DATE(`timestamp`) = CURDATE()
I guess using DATE still uses INDEX.
see the execution plan on the DEMO
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How to set iPhone UIView z index?
I want to move one view on top of another, how can I know the z index of the view, and how to move on to top?
9 Answers
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using gitignore to ignore (but not delete) files
... can update local git repository by running following command:
git update-index --assume-unchanged <file>
In this case a file is being tracked in the origin repo. You can modify it in your local repo and git will never mark it as changed. Read more at:
http://blog.pagebakers.nl/2009/01/29...
Update a dataframe in pandas while iterating row by row
...ot on the value from the iterator. The iterator value is only used for the index of the value/object. What will fail is row['ifor']=some_thing, for the reasons mentioned in the documentation.
– rakke
May 11 '16 at 12:32
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B-Tree vs Hash Table
In MySQL, an index type is a b-tree, and access an element in a b-tree is in logarithmic amortized time O(log(n)) .
5 Answ...
How can you determine how much disk space a particular MySQL table is taking up?
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For a table mydb.mytable run this for:
BYTES
SELECT (data_length+index_length) tablesize
FROM information_schema.tables
WHERE table_schema='mydb' and table_name='mytable';
KILOBYTES
SELECT (data_length+index_length)/power(1024,1) tablesize_kb
FROM information_schema.tables
WHERE table_s...
When and why are database joins expensive?
... working set. Joins involving properly selected keys with correctly set up indexes are cheap, not expensive, because they allow significant pruning of the result before the rows are materialised.
Materialising the result involves bulk disk reads which are the most expensive aspect of the exercise ...
Creating a Pandas DataFrame from a Numpy array: How do I specify the index column and column headers
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You need to specify data, index and columns to DataFrame constructor, as in:
>>> pd.DataFrame(data=data[1:,1:], # values
... index=data[1:,0], # 1st column as index
... columns=data[0,1:]) # 1st row as the co...