Programming Essentials in Python - Ch 3 PDF

Chapter 3: Basic data types and operators Python, a widely used high-level programming language, offers various built-in data types and operators. Here's a brief overview of both. 1.1 Operators These are special symbols which help the user to carry out operations like addition, subtraction, etc. Py...

Chapter 3: Basic data types and operators Python, a widely used high-level programming language, offers various built-in data types and operators. Here's a brief overview of both. 1.1 Operators These are special symbols which help the user to carry out operations like addition, subtraction, etc. Python provides following type of operators: Arithmetic operators: +, –, *, /, %, ** and //. Assignment operators: =, + =, – =, *=, /=, %=, **= and //= Logical operators: or, and, and not Relational operators: =, != or < > and ==. 1.2 Standard Data Types Data types are the classification or categorization of data items. It represents the kind of value that tells what operations can be performed on a particular data. Since everything is an object in Python programming, data types are actually 1  classes and variables are instances (object) of these classes. The data stored in memory can be of many types. Python has five main standard data types: Numbers String List Tuple Dictionary Numbers Number data types store numeric values. Number objects are created when you assign a value to them. Python supports different numerical types: int for integer numbers : Int, or integer, is a whole number, positive or negative, without decimals, of unlimited length. float for decimal numbers: Float, or "floating point number" is a number, positive or negative, containing one or more decimals. complex for complex numbers: Complex numbers are written with a "j" as the imaginary part: Variables of numeric types are created when you assign a value to them. For example x = 1 # int y = 2.8 # float z = 1j # complex 2 for example: 3 String A string is a collection of one or more characters put in a single quote, double- quote, or triple-quote. In python there is no character data type, a character is a string of length one. It is represented by str class. Creating String: Strings in Python can be created using single quotes or double quotes or even triple quotes. As you’ve already seen, you can create a string by surrounding some text with quotation marks: string1 = 'Hello, World' string2 = "1234" You can use either single quotes (string1) or double quotes (string2) to create a string as long as you use the same type at the beginning and end of the string. 4 Whenever you create a string by surrounding text with quotation marks, the string is called a string literal. The name indicates that the string is literally written out in your code. All the strings you’ve seen thus far are string literals. A string is organized as an array of characters. For example: Strings (Access character): Example 1: Example 2: 5  Example 3: To access a substring from a string, we use a string variable name followed by square brackets with starting index and ending index of the required substring. 6 For example: Strings (+, * operators) 7  Strings (Functions) Example 1: Example 2: 8  List Python Lists are just like dynamically sized arrays. A list is a collection of things, enclosed in [ ] and separated by commas. The list is a sequence data type which is used to store the collection of data. Tuples and String are other types of sequence data types. For example: Here we are creating Python List using []. Var = ["Geeks", "for", "Geeks"] print(Var) Output: ["Geeks", "for", "Geeks"] 9  Tuple A Tuple is a sequence, just like a list. The differences between tuples and lists are: the tuples cannot be changed unlike lists tuples use parentheses (), whereas lists use square brackets []. Parentheses are optional in tuples. Creating Python Tuples: How to access elements from tuple? 10 How to remove the entire tuple? Tuples (+, * operators) 11 Lists (Functions) Exercises: Lists & Tuples 12 Dictionary Dictionary in Python is a collection of keys values, used to store data values like a map, which, unlike other data types which hold only a single value as an element. For example: Dict = {1: 'Geeks', 2: 'For', 3: 'Geeks'} print(Dict) 13