Tutorial by Examples: dictionary

let myAllKeys = ["name" : "Kirit" , "surname" : "Modi"] let allKeys = Array(myAllKeys.keys) print(allKeys)

There are multiple ways to set a key's object in an NSDictionary, corresponding to the ways you get a value. For instance, to add a lamborghini to a list of cars Standard [cars setObject:lamborghini forKey:@"Lamborghini"]; Just like any other object, call the method of NSDictionary th...

There are multiple ways to get an object from an NSDictionary with a key. For instance, to get a lamborghini from a list of cars Standard Car * lamborghini = [cars objectForKey:@"Lamborghini"]; Just like any other object, call the method of NSDictionary that gives you an object for a ...

Represents a thread-safe collection of key/value pairs that can be accessed by multiple threads concurrently. Creating an instance Creating an instance works pretty much the same way as with Dictionary<TKey, TValue>, e.g.: var dict = new ConcurrentDictionary<int, string>(); Ad...

Each pair in the dictionary is an instance of KeyValuePair with the same type parameters as the Dictionary. When you loop through the dictionary with For Each, each iteration will give you one of the Key-Value Pairs stored in the dictionary. For Each kvp As KeyValuePair(Of String, String) In curren...

Dim extensions As New Dictionary(Of String, String) _ from { { "txt", "notepad" }, { "bmp", "paint" }, { "doc", "winword" } } This creates a dictionary and immediately fills it with three KeyValuePairs. You can also add new val...

You can get the value of an entry in the dictionary using the 'Item' property: Dim extensions As New Dictionary(Of String, String) From { { "txt", "notepad" }, { "bmp", "paint" }, { "doc", "winword" } } Dim program As St...

options = { "x": ["a", "b"], "y": [10, 20, 30] } Given a dictionary such as the one shown above, where there is a list representing a set of values to explore for the corresponding key. Suppose you want to explore "x"="a" w...

If you use a dictionary as an iterator (e.g. in a for statement), it traverses the keys of the dictionary. For example: d = {'a': 1, 'b': 2, 'c':3} for key in d: print(key, d[key]) # c 3 # b 2 # a 1 The same is true when used in a comprehension print([key for key in d]) # ['c', 'b', '...

Prefer dict.get method if you are not sure if the key is present. It allows you to return a default value if key is not found. The traditional method dict[key] would raise a KeyError exception. Rather than doing def add_student(): try: students['count'] += 1 except KeyError: ...

+ dictionaryWithCapacity: Creates and returns a mutable dictionary, initially giving it enough allocated memory to hold a given number of entries. NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithCapacity:1]; NSLog(@"%@",dict); - init Initializes a newly allocated mut...

- removeObjectForKey: Removes a given key and its associated value from the dictionary. NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithDictionary:@{@"key1":@"Easy",@"key2": @"Tutorials"}]; [dict removeObjectForKey:@"key1"]; NSLog...

Rules for creating a dictionary: Every key must be unique (otherwise it will be overridden) Every key must be hashable (can use the hash function to hash it; otherwise TypeError will be thrown) There is no particular order for the keys. # Creating and populating it with values stock = {'egg...

def foobar(foo=None, bar=None): return "{}{}".format(foo, bar) values = {"foo": "foo", "bar": "bar"} foobar(**values) # "foobar"

Dictionary<TKey, TValue> is a map. For a given key there can be one value in the dictionary. using System.Collections.Generic; var people = new Dictionary<string, int> { { "John", 30 }, {"Mary", 35}, {"Jack", 40} }; // Reading data Console.Wri...

Objective c: //this is the dictionary you start with. NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"name1", @"Sam",@"name2", @"Sanju",nil]; //check if the dictionary contains the key you are going to modify. In this example, @&qu...

Functions allow you to specify these types of parameters: positional, named, variable positional, Keyword args (kwargs). Here is a clear and concise use of each type. def unpacking(a, b, c=45, d=60, *args, **kwargs): print(a, b, c, d, args, kwargs) >>> unpacking(1, 2) 1 2 45 60 ()...

Subscripts can also be used with NSDictionary and NSMutableDictionary. The following code: NSMutableDictionary *myDictionary = [@{@"Foo": @"Bar"} mutableCopy]; [myDictionary setObject:@"Baz" forKey:@"Foo"]; NSLog(@"%@", [myDictionary objectForKey:...

Create a Dictionary<TKey, TValue> from an IEnumerable<T>: using System; using System.Collections.Generic; using System.Linq; public class Fruits { public int Id { get; set; } public string Name { get; set; } } var fruits = new[] { new Fruits { Id = 8 , Nam...

Starting from a dataframe df: U L 111 en 112 en 112 es 113 es 113 ja 113 zh 114 es Imagine you want to add a new column called S taking values from the following dictionary: d = {112: 'en', 113: 'es', 114: 'es', 111: 'en'} You can use map to perform a lookup on keys returni...