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Found 34486 Articles for Programming
![karthikeya Boyini](https://www.tutorialspoint.com/assets/profiles/13518/profile/60_31598-1537784993.jpg)
1K+ Views
Python and javascript both have different representations for a dictionary. So you need an intermediate representation in order to pass data between them. The most commonly used intermediate representation is JSON, which is a simple lightweight data-interchange format.ExampleThe dumps function converts the dict to a string. For example, import json my_dict = { 'foo': 42, 'bar': { 'baz': "Hello", 'poo': 124.2 } } my_json = json.dumps(my_dict) print(my_json)OutputThis will give the output:'{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}'ExampleThe load's function converts the string back to a dict. For example, import json my_str ... Read More
![Ankith Reddy](https://www.tutorialspoint.com/assets/profiles/22328/profile/60_142162-1519038074.jpg)
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A python dictionary is a Hashmap. You can use the map data structure in C++ to mimic the behavior of a python dict. You can use map in C++ as follows:#include #include using namespace std; int main(void) { /* Initializer_list constructor */ map m1 = { {'a', 1}, {'b', 2}, {'c', 3}, {'d', 4}, {'e', 5} }; cout
![Samual Sam](https://www.tutorialspoint.com/assets/profiles/13514/profile/60_83486-1512649303.jpg)
351 Views
There are many C++/Python bindings. It boils down to what you use to communicate between C++ and python to read python dictionaries in c++. Most of these libraries(like Boost) handle the parsing themselves. You could use an intermediate data transfer format like JSON or XML to pass data between the 2 languages and then serialize and deserialize data using the respective libraries in these languages for these formats.
![Lakshmi Srinivas](https://www.tutorialspoint.com/assets/profiles/13528/profile/60_91717-1512651120.jpg)
129 Views
You can sort a list of dictionaries by values of the dictionary using the sorted function and passing it a lambda that tells which key to use for sorting. For example, A = [{'name':'john', 'age':45}, {'name':'andi', 'age':23}, {'name':'john', 'age':22}, {'name':'paul', 'age':35}, {'name':'john', 'age':21}] new_A = sorted(A, key=lambda x: x['age']) print(new_A)This will give the output:[{'name': 'john', 'age': 21}, {'name': 'john', 'age': 22}, {'name': 'andi', 'age': 23}, {'name': 'paul', 'age': 35}, {'name': 'john', 'age': 45}]You can also sort it in place using the sort function instead of the sorted function. For example, A ... Read More
![karthikeya Boyini](https://www.tutorialspoint.com/assets/profiles/13518/profile/60_31598-1537784993.jpg)
2K+ Views
If you have a dictionary of the following format:{ 'KEY1':{'name':'foo', 'data':1351, 'completed':100}, 'KEY2':{'name':'bar', 'data':1541, 'completed':12}, 'KEY3':{'name':'baz', 'data':58413, 'completed':18} }And you want to sort by the key, completed within each entry, in a ascending order, you can use the sorted function with a lambda that specifies which key to use to sort the data. For example, my_collection = { 'KEY1':{'name':'foo', 'data':1351, 'completed':100}, 'KEY2':{'name':'bar', 'data':1541, 'completed':12}, 'KEY3':{'name':'baz', 'data':58413, 'completed':18} } sorted_keys = sorted(my_collection, key=lambda x: (my_collection[x]['completed'])) print(sorted_keys)This will give the output:['KEY2', 'KEY3', 'KEY1']Read More
![Samual Sam](https://www.tutorialspoint.com/assets/profiles/13514/profile/60_83486-1512649303.jpg)
208 Views
dicts in python are heavily optimized. Creating a dict from N keys or key/value pairs is O(N), fetching is O(1), putting is amortized O(1), and so forth. You don't need to optimize them explicitly. You can be sure of this as python under the hood implements its own classes using dicts.Don't compare lists/tuples to dicts/sets though as they solve different problems.
![Monica Mona](https://www.tutorialspoint.com/assets/profiles/13520/profile/60_87298-1512650151.jpg)
661 Views
When using the old style of string formatting in python, ie, "" % (), if the thing after the percent is a tuple, python tries to break it down and pass individual items in it to the string. For example, tup = (1, 2, 3) print("this is a tuple %s" % (tup))This will give the output:TypeError: not all arguments converted during string formattingThis is because of the reason mentioned above. If you want to pass a tuple, you need to create a wrapping tuple using the (tup, ) syntax. For example, tup = (1, 2, 3) print("this is a tuple ... Read More
![Chandu yadav](https://www.tutorialspoint.com/assets/profiles/22330/profile/60_142811-1519038104.jpg)
568 Views
The str function converts an object in python to a string representation. There is another function called repr() in python that converts object to an expression string. __repr__'s goal is to be unambigous while __str__'s is to be readable. __repr__ is used to compute the “official” string representation of an object.ExampleLet's take an example of datetime to understand what these 2 produce.import datetime today = datetime.datetime.now() str(today) repr(today)OutputThis will give the output'2018-04-08 11:25:36.918979' 'datetime.datetime(2018, 4, 8, 11, 25, 36, 918979)'As you can see from the output, str gives a pretty, formatted result. Repr just throws an object constructor representation at ... Read More
![karthikeya Boyini](https://www.tutorialspoint.com/assets/profiles/13518/profile/60_31598-1537784993.jpg)
3K+ Views
To convert a tuple to an array(list) you can directly use the list constructor. examplex = (1, 2, 3) y = list(x) print(y)OutputThis will give the output −[1, 2, 3]ExampleIf you have a multi-level tuple and want a flat array, you can use the following −z = ((1, 2, 3), (4, 5)) y = [a for b in z for a in b] print(y)OutputThis will give the output −[1, 2, 3, 4, 5]