Beginner’s Guide to Python

Machine Learning for Beginners in Python: Loading Features From Dictionaries

Hits: 7 Loading Features From Dictionaries from sklearn import datasets import numpy as np iris = datasets.load_iris() X = iris.data[:, [2, 3]] X array([[1.4, 0.2], [1.4, 0.2], [1.3, 0.2], [1.5, 0.2], [1.4, 0.2], [1.7, 0.4], [1.4, 0.3], [1.5, 0.2], [1.4, 0.2], [1.5, 0.1], [1.5, 0.2], [1.6, 0.2], [1.4, 0.1], [1.1, 0.1], [1.2, 0.2], [1.5, 0.4], …

Python Built-in Methods – Python Dictionary values() Method

Hits: 17 Python Dictionary values() Method Returns a list of values from a dictionary Usage The values() method returns a list of values from a dictionary. Syntax dictionary.values() Examples # Print all values from the dictionary D = {‘name’: ‘Bob’, ‘age’: 25} L = D.values() print(L) # Prints dict_values([25, ‘Bob’]) values() method is generally used to iterate through all …

Python Built-in Methods – Python Dictionary update() Method

Hits: 10 Python Dictionary update() Method Updates/Adds multiple items to the dictionary Usage The update() method updates the dictionary with the key:value pairs from element. If the key is already present in the dictionary, value gets updated. If the key is not present in the dictionary, a new key:value pair is added to the dictionary. element can be either another dictionary …

Python Built-in Methods – Python Dictionary setdefault() Method

Hits: 2 Python Dictionary setdefault() Method Returns the value for key if exists, else inserts it Usage The setdefault() method returns the value for key if key is in the dictionary. If not, it inserts key with a value of default and returns default. Syntax dictionary.setdefault(key,default) Parameter Condition Description key Required Any key you want to return value for default Optional A value to …

Python Built-in Methods – Python Dictionary popitem() Method

Hits: 26 Python Dictionary popitem() Method Removes a key-value pair from a dictionary Usage The popitem() method removes and returns the last inserted key:value pair from the dictionary. Pairs are returned in Last In First Out (LIFO) order. In versions before 3.7, popitem() would remove and return a random item. Syntax dictionary.popitem() Examples # Remove the last inserted item from the dictionary D = …

Python Built-in Methods – Python Dictionary pop() Method

Hits: 10 Python Dictionary pop() Method Removes a key from the dictionary Usage If specified key is in the dictionary, the pop() method removes it and returns its value. You can also specify the default parameter that will be returned if the specified key is not found. If default is not specified and key is not in the dictionary, a KeyError is raised. Syntax dictionary.pop(key,default) Parameter …

Python Built-in Methods – Python Dictionary items() Method

Hits: 8 Python Dictionary items() Method Returns a list of key-value pairs in a dictionary Usage The items() method returns a list of tuples containing the key:value pairs of the dictionary. The first item in each tuple is the key, and the second item is its associated value. Syntax dictionary.items() Examples # Print all items from the dictionary …

Python Built-in Methods – Python Dictionary get() Method

Hits: 6 Python Dictionary get() Method Returns the value for key if exists Usage The get() method returns the value for key if key is in the dictionary. You can also specify the default parameter that will be returned if the specified key is not found. If default is not specified, it returns None. Therefore, this method never raises a KeyError. It’s an easy way of …

Python Built-in Methods – Python Dictionary copy() Method

Hits: 7 Python Dictionary copy() Method Copies the dictionary shallowly Usage The copy() method returns the Shallow copy of the specified dictionary. Syntax dictionary.copy() Example D = {‘name’: ‘Bob’, ‘age’: 25} X = D.copy() print(X) # Prints {‘age’: 25, ‘name’: ‘Bob’} copy() vs Assignment statement Assignment statement does not copy objects. For example, old_Dict = {‘name’: ‘Bob’, ‘age’: 25} new_Dict …

Python Built-in Methods – Python Dictionary clear() Method

Hits: 2 Python Dictionary clear() Method Removes all items from the dictionary Usage Use clear() method to remove all items from the dictionary. This method does not return anything; it modifies the dictionary in place. Syntax dictionary.clear() Example D = {‘name’: ‘Bob’, ‘age’: 25} D.clear() print(D) # Prints {} clear() vs Assigning Empty Dictionary Assigning an empty dictionary D …

Python Built-in Methods – Python Set update() Method

Hits: 10 Python Set update() Method Updates the set by adding items from all the specified sets Usage The update() method updates the original set by adding items from all the specified sets, with no duplicates. You can specify as many sets as you want, just separate each set with a comma. If you don’t want to update the original set, …

Python Built-in Methods – Python Set symmetric_difference_update() Method

Hits: 5 Python Tuple count() Method Python Set symmetric_difference_update() Method Updates the set by keeping only elements found in either set, but not in both Usage The symmetric_difference_update() method updates the set by keeping only elements found in either set, but not in both. If you don’t want to update the original set, use symmetric_difference() method. The symmetric difference is actually …

Python Built-in Methods – Python Set symmetric_difference() Method

Hits: 10 Python Set symmetric_difference() Method Returns a new set with items from all the sets, except common items Usage The symmetric_difference() method returns a new set containing all items from both the sets, except common items. If you want to modify the original set instead of returning a new one, use symmetric_difference_update() method. The symmetric difference is actually the union of the two …

Python Built-in Methods – Python Set remove() Method

Hits: 5 Python Set remove() Method Removes a specified item from the set Usage The remove() method removes a specified item from the set. If specified item is not present in the set, the method raises KeyError. Syntax set.remove(item) Parameter Condition Description item Required An item you want to remove from the set Examples # Remove ‘red’ from the set S = {‘red’, …