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C++ map access discards qualifiers (const)
...k up a key without modifying the map.
find() returns an iterator, or const_iterator to an std::pair containing both the key (.first) and the value (.second).
In C++11, you could also use at() for std::map. If element doesn't exist the function throws a std::out_of_range exception, in contrast to o...
Iterating over Java collections in Scala
...ares the appropriate conversions.
import scala.collection.JavaConversions._
This won't work in previous versions though.
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Why is it string.join(list) instead of list.join(string)?
...ct, set), but the result and the "joiner" must be strings.
For example:
'_'.join(['welcome', 'to', 'stack', 'overflow'])
'_'.join(('welcome', 'to', 'stack', 'overflow'))
'welcome_to_stack_overflow'
Using something else than strings will raise the following error:
TypeError: sequence item 0...
Bin size in Matplotlib (Histogram)
...width in this example could be found by: (data.max() - data.min()) / number_of_bins_you_want. The + binwidth could be changed to just 1 to make this a more easily understood example.
– Jarad
Jan 22 '18 at 17:31
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How to set environment variables in Python?
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@darth_coder It's true for all processes on Unix-like operating systems. I don't know about the other operating system. Note that shell variables are not stored in the environment unless you export them.
– S...
Create an empty list in python with certain size
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you can do this: a = [0 for _ in range(10)]
– Kamiar
Dec 19 '18 at 21:55
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Meaning of 'const' last in a function declaration of a class?
...e that is often broken and easily broken.
foobar& fbNonConst = const_cast<foobar&>(fb1);
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Remove blank attributes from an Object in Javascript
...a simple solution:
var obj = {name: 'John', age: null};
var compacted = _.pickBy(obj);
This will only work with lodash 4, pre lodash 4 or underscore.js, use _.pick(obj, _.identity);
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MongoDB Aggregation: How to get total records count?
...te(array(
array('$match' => $document),
array('$group' => array('_id' => '$book_id', 'date' => array('$max' => '$book_viewed'), 'views' => array('$sum' => 1))),
array('$sort' => $sort),
// get total, AND preserve the results
array('$group' => array('_id' => nu...
How to find elements by class
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@pyCthon See answer for @jmunsch, BS now supports class_ which works properly.
– Wernight
Oct 6 '14 at 9:47
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