You can use $project & $unwind & $group of aggregation framework to get the result closer to your requirement. > db.countries.aggregate({$project:{a:’$data.country.neighbor.name’}}, {$unwind:’$a’}, {$unwind:’$a’}, {$group:{_id:’a’,res:{$addToSet:’$a’}}}) { “result” : [ { “_id” : “a”, “res” : [ “Colombia”, “Malaysia”, “Switzerland”, “Costa Rica”, “Austria” ] } ], “ok” : 1 } $unwind used twice since the name array … Read more
Take a look at numpy.reshape . >>> arr = numpy.zeros((50,100,25)) >>> arr.shape # (50, 100, 25) >>> new_arr = arr.reshape(5000,25) >>> new_arr.shape # (5000, 25) # One shape dimension can be -1. # In this case, the value is inferred from # the length of the array and remaining dimensions. >>> another_arr = arr.reshape(-1, arr.shape[-1]) … Read more
The reset_index() is a pandas DataFrame method that will transfer index values into the DataFrame as columns. The default setting for the parameter is drop=False (which will keep the index values as columns). All you have to do call .reset_index() after the name of the DataFrame: df = df.reset_index()
As of PHP 5.3 the shortest solution seems to be array_walk_recursive() with the new closures syntax: function flatten(array $array) { $return = array(); array_walk_recursive($array, function($a) use (&$return) { $return[] = $a; }); return $return; }
The current API is that: flatten always returns a copy. ravel returns a view of the original array whenever possible. This isn’t visible in the printed output, but if you modify the array returned by ravel, it may modify the entries in the original array. If you modify the entries in an array returned from … Read more
Using generator functions can make your example easier to read and improve performance. Python 2 Using the Iterable ABC added in 2.6: from collections import Iterable def flatten(xs): for x in xs: if isinstance(x, Iterable) and not isinstance(x, basestring): for item in flatten(x): yield item else: yield x Python 3 In Python 3, basestring is … Read more
You can use concat to merge arrays: var arrays = [ [“$6”], [“$12”], [“$25”], [“$25”], [“$18”], [“$22”], [“$10”] ]; var merged = [].concat.apply([], arrays); console.log(merged); Using the apply method of concat will just take the second parameter as an array, so the last line is identical to this: var merged2 = [].concat([“$6”], [“$12”], [“$25”], [“$25”], … Read more