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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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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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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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Fast way of counting non-zero bits in positive integer
I need a fast way to count the number of bits in an integer in python.
My current solution is
9 Answers
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Simultaneously merge multiple data.frames in a list
...o merge. The issue here is that each data.frame differs in terms of the number of rows and columns, but they all share the key variables (which I've called "var1" and "var2" in the code below). If the data.frames were identical in terms of columns, I could merely rbind , for which plyr's rbind...
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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How are the points in CSS specificity calculated
Researching specificity I stumbled upon this blog - http://www.htmldog.com/guides/cssadvanced/specificity/
7 Answers
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git rebase, keeping track of 'local' and 'remote'
When doing a git rebase, I often have difficulty working out what is happening with the 'local' and 'remote' when resolving conflicts. I sometimes have the impression that they swap sides from one commit to the next.
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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...
Math - mapping numbers
How do I map numbers, linearly, between a and b to go between c and d.
9 Answers
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