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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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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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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 sort a dataFrame in python pandas by two or more columns?
... pd.DataFrame(np.random.randint(1, 5, (10,2)), columns=['a','b'])
df1 = pd.concat([df1]*100000)
def pdsort(df1):
return df1.sort_values(['a', 'b'], ascending=[True, False])
def lex(df1):
arr = df1.values
return pd.DataFrame(arr[np.lexsort((-arr[:, 1], arr[:, 0]))])
assert (pdsort(df1)...
Creating C macro with ## and __LINE__ (token concatenation with positioning macro)
...or is expected to for decades. The prime example is compiling X11, macro "Concat3" is broken, it's result is now MISNAMED C Identifier, which of course fails to build. and i'm beginning to thing build fails are their profession.
I think the answer here is "new C that breaks standards is bad C", t...
How can I generate random alphanumeric strings?
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@Adam: Yes, you could concat the result of multiple calls to GetRandomFileName but then (a) you'd lose your performance advantage, and (b) your code would become more complicated.
– LukeH
Aug 28 '09 at 9:08
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How do you specify that a class property is an integer?
...ponential, toFixed, toPrecision, toString
myString. // charAt, charCodeAt, concat, indexOf, lastIndexOf, length and many more...
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Tab space instead of multiple non-breaking spaces (“nbsp”)?
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Was looking for this when building a large concat() query in MySQL for use in a Crystal Report. the ASCII (	) did the job perfectly!
– MikeMighty
Mar 9 '18 at 14:40
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Convert pandas dataframe to NumPy array
...early the same (actually, using rec.fromrecords is a bit faster).
df2 = pd.concat([df] * 10000)
%timeit df2.to_records()
%%timeit
v = df2.reset_index()
np.rec.fromrecords(v, names=v.columns.tolist())
11.1 ms ± 557 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
9.67 ms ± 126 µs per l...
Initialization of an ArrayList in one line
...e:
Stream<String> strings = Stream.of("foo", "bar", "baz");
You can concatenate Streams:
Stream<String> strings = Stream.concat(Stream.of("foo", "bar"),
Stream.of("baz", "qux"));
Or you can go from a Stream to a List:
import static java.util.strea...