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Python Examples

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Python Syntax

Print "Hello World" Comments in Python Docstrings

Syntax Explained

Python Variables

Create a variable Output both text and a variable Add a variable to another variable

Variables Explained

Python Numbers

Verify the type of an object Create integers Create floating point numbers Create scientific numbers with an "e" to indicate the power of 10 Create complex numbers

Numbers Explained

Python Casting

Casting - Integers Casting - Floats Casting - Strings

Casting Explained

Python Strings

Get the character at position 1 of a string Substring. Get the characters from position 2 to position 5 (not included) Remove whitespace from the beginning or at the end of a string Return the length of a string Convert a string to lower case Convert a string to upper case Replace a string with another string Split a string into substrings

Strings Explained

Python Operators

Addition operator Subtraction operator Multiplication operator Division operator Modulus operator Assignment operator

Operators Explained

Python Lists

Create a list Access list items Change the value of a list item Loop through a list Check if a list item exists Get the length of a list Add an item to the end of a list Add an item at a specified index Remove an item Remove the last item Remove an item at a specified index Empty a list Using the list() constructor to make a list

Lists Explained

Python Tuples

Create a tuple Access tuple items Change tuple values Loop through a tuple Check if a tuple item exists Get the length of a tuple Delete a tuple Using the tuple() constructor to create a tuple

Tuples Explained

Python Sets

Create a set Loop through a set Check if an item exists Add an item to a set Add multiple items to a set Get the length of a set Remove an item in a set Remove an item in a set by using the discard() method Remove the last item in a set by using the pop() method Empty a set Delete a set Using the set() constructor to create a set

Sets Explained

Python Dictionaries

Create a dictionary Access the items of a dictionary Change the value of a specific item in a dictionary Print all key names in a dictionary, one by one Print all values in a dictionary, one by one Using the values() function to return values of a dictionary Loop through both keys an values, by using the items() function Check if a key exists Get the length of a dictionary Add an item to a dictionary Remove an item from a dictionary Empty a dictionary Using the dict() constructor to create a dictionary

Dictionaries Explained

Python If ... Else

The if statement The elif statement The else statement Short hand if Short hand if ... else The and keyword The or keyword

If ... Else Explained

Python While Loop

The while loop Using the break statement in a while loop Using the continue statement in a while loop

While Loop Explained

Python For Loop

The for loop Loop through a string Using the break statement in a for loop Using the continue statement in a for loop Using the range() function in a for loop Else in for loop Nested for loop

For Loop Explained

Python Functions

Create and call a function Function parameters Default parameter value Let a function return a valuen Recursion

Functions Explained

Python Lambda

A lambda function that adds 10 to the number passed in as an argument A lambda function that multiplies argument a with argument b A lambda function that sums argument a, b, and c

Lambda Explained

Python Arrays

Create an array Access the elements of an array Change the value of an array element Get the length of an array Loop through all elements of an array Add an element to an array Remove an element from an array

Arrays Explained

Python Classes and Objects

Create a class Create an object The __init__() Function Create object methods The self parameter Modify object properties Delete object properties Delete an object

Classes/Objects Explained

Python Iterators

Return an iterator from a tuple Return an iterator from a string Loop through an iterator Create an iterator Stop iteration

Iterators Explained

Python Modules

Use a module Variables in module Re-naming a module Built-in modules Using the dir() function Import from module

Modules Explained

Python Dates

Import the datetime module and display the current date Return the year and name of weekday Create a date object The strftime() Method

Dates Explained

Python JSON

Convert from JSON to Python Convert from Python to JSON Convert Python objects into JSON strings Convert a Python object containing all the legal data types Use the indent parameter to define the numbers of indents Use the separators parameter to change the default separator Use the sort_keys parameter to specify if the result should be sorted or not

JSON Explained

Python RegEx

Search a string to see if it starts with "The" and ends with "Spain" Using the findall() function Using the search() function Using the split() function Using the sub() function

RegEx Explained

Python PIP

Using a package

PIP Explained

Python Try Except

When an error occurs, print a message Many exceptions Use the else keyword to define a block of code to be executed if no errors were raised Use the finally block to execute code regardless if the try block raises an error or not

Try Except Explained

Python Files

Read a file Read only parts of a file Read one line of a file Loop through the lines of a file to read the whole file, line by line

Files Explained

Python MySQL

Create a connection to a database Create a database in MySQL Check if a database exist Create a table Check if a table exist Create primary key when creating a table Insert a record in a table Insert multiple rows Get inserted ID Select all records from a table Select only some of the columns in a table Use the fetchone() method to fetch only one row in a table Select with a filter Wildcards characters Prevent SQL injection Sort the result of a table alphabetically Sort the result in a descending order (reverse alphabetically) Delete records from an existing table Prevent SQL injection Delete an existing table Delete a table if it exist Update existing records in a table Prevent SQL injection Limit the number of records returned from a query Combine rows from two or more tables, based on a related column between them LEFT JOIN RIGHT JOIN

MySQL Explained

Python MongoDB

Create a database Check if a database exist Create a collection Check if a collection exist Insert into collection Return the id field Insert multiple documents Insert multiple documents with specified IDs Find the first document in the selection Find all documents in the selection Find only some fields Filter the result Advanced query Filter with regular expressions Sort the result alphabetically Sort the result descending (reverse alphabetically) Delete document Delete many documents Delete all documents in a collection Delete a collection Update a document Update many/all documents Limit the result

MongoDB Explained

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