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How can I pass a member function where a free function is expected?
...ing wrong with using function pointers. However, pointers to non-static member functions are not like normal function pointers: member functions need to be called on an object which is passed as an implicit argument to the function. The signature of your member function above is, thus
void (aClass:...
pandas: multiple conditions while indexing data frame - unexpected behavior
I am filtering rows in a dataframe by values in two columns.
3 Answers
3
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What's the algorithm to calculate aspect ratio?
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I gather you're looking for an usable aspect ratio integer:integer solution like 16:9 rather than a float:1 solution like 1.77778:1.
If so, what you need to do is find the greatest common divisor (GCD) and divide both values by that. The GCD is the highest n...
Do the parentheses after the type name make a difference with new?
If 'Test' is an ordinary class, is there any difference between:
6 Answers
6
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Sample random rows in dataframe
...ruggling to find the appropriate function that would return a specified number of rows picked up randomly without replacement from a data frame in R language? Can anyone help me out?
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Why are elementwise additions much faster in separate loops than in a combined loop?
Suppose a1 , b1 , c1 , and d1 point to heap memory and my numerical code has the following core loop.
10 Answers
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Return anonymous type results?
Using the simple example below, what is the best way to return results from multiple tables using Linq to SQL?
16 Answers
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Listing all permutations of a string/integer
...f interviews though) is to take a string or an integer and list every possible permutation.
28 Answers
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count the frequency that a value occurs in a dataframe column
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Use groupby and count:
In [37]:
df = pd.DataFrame({'a':list('abssbab')})
df.groupby('a').count()
Out[37]:
a
a
a 2
b 3
s 2
[3 rows x 1 columns]
See the online docs: http://pandas.pydata.org/pandas-docs/stable/groupby.htm...
SQL JOIN vs IN performance?
...g a JOIN or an IN will give me the correct results... Which typically has better performance and why? How much does it depend on what database server you are running? (FYI I am using MSSQL)
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