By default, PyYAML chooses the style of a collection depending on whether it has nested collections. If a collection has nested collections, it will be assigned the block style. Otherwise it will have the flow style. If you want collections to be always serialized in the block style, set the parameter default_flow_style of dump() to … Read more
You should probably call dict.__init__(self) when subclassing; in fact, you don’t know what’s happening precisely in dict (since it’s a builtin), and that might vary across versions and implementations. Not calling it may result in improper behaviour, since you can’t know where dict is holding its internal data structures. By the way, you didn’t tell … Read more
The os.environ documentation does state it’s a mapping: A mapping object representing the string environment. As such it behaves according to the python mapping documentation of which dict is the standard implementation. os.environ therefor behaves just like the standard dict, it has all the same methods: >>> import os >>> len(os.environ) 36 >>> ‘USER’ in … Read more
I would implement a data structure with these two dictionaries Dictionary<TKey1, KeyValuePair<TKey2, TValue>> dict1; Dictionary<TKey2, KeyValuePair<TKey1, TValue>> dict2; That way if you are given 1 key you have both the value and the other key as well for easy deletes and updates.
Short answer: no. Long answer: nope. It should be noted that C++14‘s support for transparent comparators eliminates the need for Boost.Bimap 90% of the time*: when you need to key off of any given property of an object (stored or computed), often a simple, bitwise-comparable unique identifier inherent to/present in the object anyway. With transparent … Read more
There is no standard small implementation of Map in Java. HashMap is one of the best and most flexible Map implementations around, and is hard to beat. However, in the very small requirement area — where heap usage and speed of construction is paramount — it is possible to do better. I have implemented SmallCollections … Read more
Deletion of map elements The built-in function delete removes the element with key k from a map m. delete(m, k) // remove element m[k] from map m For example, package main import “fmt” func main() { m := map[string]string{“key1”: “val1”, “key2”: “val2”} fmt.Println(m) delete(m, “key1”) fmt.Println(m) } Output: map[key1:val1 key2:val2] map[key2:val2]
In Python, the average time complexity of a dictionary key lookup is O(1), since they are implemented as hash tables. The time complexity of lookup in a list is O(n) on average. In your code, this makes a difference in the line if tmp not in num:, since in the list case, Python needs to … Read more
groupBy as defined on TraversableLike produces an immutable.Map, so you can’t make this method produce something else. The order of the elements in each entry is already preserved, but not the order of the keys. The keys are the result of the function supplied, so they don’t really have an order. If you wanted to … Read more
In Java primitives aren’t objects, so you can’t use them in place of objects. However Java will automatically box/unbox primitives (aka autoboxing) into objects so you can do things like: List<Integer> intList = new LinkedList<Integer>(); intList.add(1); intList.add(new Integer(2)); … Integer first = intList.get(0); int second = intList.get(1); But this is really just the compiler automatically … Read more