Python Articles

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How can we do Python operator overloading with multiple operands?

Sravani S
Sravani S
Updated on 05-Mar-2020 445 Views

You can do Python operator overloading with multiple operands just like you would do it for binary operators. For example, if you want to overload the + operator for a class, you'd do the following −Exampleclass Complex(object): def __init__(self, real, imag): self.real = real self.imag = imag def __add__(self, other): real = self.real + other.real imag = self.imag + other.imag return Complex(real, imag) def display(self): print(str(self.real) + " + " + str(self.imag) + "i") a = Complex(10, 5) b = Complex(5, 10) c = Complex(2, 2) d = a + b + c d.display()OutputThis will give the output −17 + 17i

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How to view a list of all Python operators via the interpreter?

Lakshmi Srinivas
Lakshmi Srinivas
Updated on 05-Mar-2020 368 Views

The help method in the interpreter is very useful for such operations. It provides a rich set of special inputs that you can give to it to get information about the different aspects of the language. Forgetting operator lists, here are some of the commands you can use:All operators>>> help('SPECIALMETHODS')Basic operators>>> help('BASICMETHODS')Numeric operators>>> help('NUMBERMETHODS')Other than operators you can also get attribute methods, callable methods, etc using −>>> help('MAPPINGMETHODS') >>> help('ATTRIBUTEMETHODS') >>> help('SEQUENCEMETHODS1') >>> help('SEQUENCEMETHODS2') >>> help('CALLABLEMETHODS')

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What do the =+ and += do in Python?

vanithasree
vanithasree
Updated on 05-Mar-2020 246 Views

The += operator is syntactic sugar for object.__iadd__() function. From the python docs:These methods are called to implement the augmented arithmetic assignments (+=, -=, *=, @=, /=, //=, %=, **=, =, &=, ^=, |=). These methods should attempt to do the operation in-place (modifying self) and return the result (which could be, but does not have to be, self).ExampleSo when you do something like −a = 5 b = 10 a += b print(a)OutputThis will give the output −15a is being modified in place here. You can read more about such operators on https://docs.python.org/3/reference/datamodel.html#object.__iadd__.The =+ operator is the same as ...

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How to find the average of non-zero values in a Python dictionary?

Lakshmi Srinivas
Lakshmi Srinivas
Updated on 05-Mar-2020 3K+ Views

You can do this by iterating over the dictionary and filtering out zero values first. Then take the sum of the filtered values. Finally, divide by the number of these filtered values. examplemy_dict = {"foo": 100, "bar": 0, "baz": 200} filtered_vals = [v for _, v in my_dict.items() if v != 0] average = sum(filtered_vals) / len(filtered_vals) print(average)OutputThis will give the output −150.0You can also use reduce but for a simple task such as this, it is an overkill. And it is also much less readable than using a list comprehension.

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Finding The Biggest Key In A Python Dictionary?

Samual Sam
Samual Sam
Updated on 05-Mar-2020 2K+ Views

If you have a dict with string-integer mappings, you can use the max method on the dictionary's item pairs to get the largest value. exampled = {    'foo': 100,    'bar': 25,    'baz': 360 } print(max(k for k, v in d.items()))OutputThis will give the output −foofoo is largest in alphabetical order.

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Do you think Python Dictionary is really Mutable?

karthikeya Boyini
karthikeya Boyini
Updated on 05-Mar-2020 309 Views

Yes, Python Dictionary is mutable. Changing references to keys doesn't lead to the creation of new dictionaries. Rather it updates the current dictionary in place. examplea = {'foo': 1, 'bar': 12} b = a b['foo'] = 20 print(a) print(b)OutputThis will give the output −{'foo': 20, 'bar': 12} {'foo': 20, 'bar': 12}

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How can I convert Python dictionary to JavaScript hash table?

radhakrishna
radhakrishna
Updated on 05-Mar-2020 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.The dumps function converts the dict to a string. exampleimport 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. import json my_str = '{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}' my_dict ...

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How to convert a spreadsheet to Python dictionary?

Samual Sam
Samual Sam
Updated on 05-Mar-2020 6K+ Views

The easiest way to convert a spreadsheet to Python dictionary is to use an external library like pandas. This provides very helpful features like to_dict on excel objects. You can use these like −Examplefrom pandas import * xls = ExcelFile('my_file.xls') data = xls.parse(xls.sheet_names[0]) print(data.to_dict())OutputThis will give the output −{'id': 10, 'name': "John"}

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How do I serialize a Python dictionary into a string, and then back to a dictionary?

Arjun Thakur
Arjun Thakur
Updated on 05-Mar-2020 1K+ Views

The JSON module is a very reliable library to serialize a Python dictionary into a string, and then back to a dictionary. The dumps function converts the dict to a string. exampleimport 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}}'The loads function converts the string back to a dict. exampleimport json my_str = '{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}' my_dict = json.loads(my_str) print(my_dict['bar']['baz'])OutputThis will give the output −Hello

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How do we grep a particular keyword from Python tuple?

Lakshmi Srinivas
Lakshmi Srinivas
Updated on 05-Mar-2020 269 Views

If you have a tuple of strings and you want to search for a particular string, You can use the in operator. exampletpl = ("Hello", "world", "Foo", "bar") print("world" in tpl)OutputThis will give the output −TrueExampleIf you want to check if there is a substring present. You can loop over the tuple and find it using:tpl = ("Hello", "world", "Foo", "bar") for i in tpl:    if "orld" in i:       print("Found orld in " + i )OutputThis will give the output −Found orld in world

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