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Why is std::map implemented as a red-black tree?
... tables with unordered_map. You can see from the documentation it requires setting policies to configure many of these options.)
What about other trees?
Red Black trees offer fast lookup and are self balancing, unlike BSTs. Another user pointed out its advantages over the self-balancing AVL tree. ...
How do I create an empty array/matrix in NumPy?
...ding rows, your best bet is to create an array that is as big as your data set will eventually be, and then add data to it row-by-row:
>>> import numpy
>>> a = numpy.zeros(shape=(5,2))
>>> a
array([[ 0., 0.],
[ 0., 0.],
[ 0., 0.],
[ 0., 0.],
[ 0., 0.]])
&...
Multiple variables in a 'with' statement?
...
is it possible set fields equal to something in with statement as in with open('./file') as arg.x = file:?
– Charlie Parker
Feb 3 '17 at 5:46
...
What is a pre-revprop-change hook in SVN, and how do I create it?
... and save it in the \hooks subdirectory for your repository.
@ECHO OFF
:: Set all parameters. Even though most are not used, in case you want to add
:: changes that allow, for example, editing of the author or addition of log messages.
set repository=%1
set revision=%2
set userName=%3
set propertyN...
Can someone give an example of cosine similarity, in a very simple, graphical way?
...o the vectors.
VERY similar documents (again with regards to this limited set of dimensions) would have the very same number of references to Paris, AND the very same number of references to London, or maybe, they could have the same ratio of these references. A Document, Doc2, with 2 refs to Paris...
C++ Object Instantiation
...
On the contrary, you should always prefer stack allocations, to the extent that as a rule of thumb, you should never have new/delete in your user code.
As you say, when the variable is declared on the stack, its destructor is automatically called when it goes ou...
Why is it slower to iterate over a small string than a small list?
...f (index < 0 || index >= PyUnicode_GET_LENGTH(self)) {
PyErr_SetString(PyExc_IndexError, "string index out of range");
return NULL;
}
kind = PyUnicode_KIND(self);
data = PyUnicode_DATA(self);
ch = PyUnicode_READ(kind, data, index);
if (ch < 256)
r...
Read an Excel file directly from a R script
...heet = 2)
# If NAs are represented by something other than blank cells,
# set the na argument
read_excel("my-spreadsheet.xls", na = "NA")
Note that while the description says 'no external dependencies', it does require the Rcpp package, which in turn requires Rtools (for Windows) or Xcode (for OS...
SQL - Update multiple records in one query
... config t2
ON t1.config_name = 'name1' AND t2.config_name = 'name2'
SET t1.config_value = 'value',
t2.config_value = 'value2';
Here is SQLFiddle demo
or conditional update
UPDATE config
SET config_value = CASE config_name
WHEN 'name1' THEN 'value'
...
How do I read / convert an InputStream into a String in Java?
...(Apache Utils)
String result = IOUtils.toString(inputStream, StandardCharsets.UTF_8);
Using CharStreams (Guava)
String result = CharStreams.toString(new InputStreamReader(
inputStream, Charsets.UTF_8));
Using Scanner (JDK)
Scanner s = new Scanner(inputStream).useDelimiter("\\A");
Strin...