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How to access pandas groupby dataframe by key
...ionally - turn it all back into a single dataframe object
sampled_df = pd.concat(df_list, axis=0, join='outer')
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How to find current transaction level?
... SET
ansi_padding SET
ansi_nulls SET
concat_null_yields_null SET
isolation level read committed
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Is there any difference between GROUP BY and DISTINCT
...s. Use GROUPY BY if you want to apply aggregate operators (MAX, SUM, GROUP_CONCAT, ..., or a HAVING clause).
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Can we make unsigned byte in Java
... for the `unsignedByte` variable,
* i.e. `short`, `int`, `long` and even `char`, but during bitwise operations
* it would get casted to `int` anyway.
*/
void printUnsignedByte(byte b) {
int unsignedByte = b & 0xFF;
System.out.println(unsignedByte); // "200"
}
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What is the best way to concatenate two vectors?
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Depends on whether you really need to physically concatenate the two vectors or you want to give the appearance of concatenation of the sake of iteration. The boost::join function
http://www.boost.org/doc/libs/1_43_0/libs/range/doc/html/range/reference/utilities/join.html
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C# equivalent to Java's charAt()?
I know we can use the charAt() method in Java get an individual character in a string by specifying its position. Is there an equivalent method in C#?
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Print all but the first three columns
.../,"")}1'
4 5 6
If you have an FS that's an RE you can't negate in a character set, you can convert it to a single char first (RS is ideal if it's a single char since an RS CANNOT appear within a field, otherwise consider SUBSEP), then apply the RE interval subsitution, then convert to the OFS...
What's the best way to do a backwards loop in C/C#/C++?
...mpile time, if given a pointer:
template<typename T, std::size_t N> char (& array_size(T(&)[N]) )[N];
It works by getting the size of the passed array first, and then declaring to return a reference to an array of type char of the same size. char is defined to have sizeof of: 1. So ...
Capture characters from standard input without waiting for enter to be pressed
...up so infrequently for me. But in C or C++, what is the best way to read a character from standard input without waiting for a newline (press enter).
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Is it possible to use “/” in a filename?
...ot something that should ever be done, but is there a way to use the slash character that normally separates directories within a filename in Linux?
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