Python programming

String operations Words and sentences are collections of characters, and so are Python strings. You can access any character in a Python string using its index, either counting from the beginning or the end of the string. When you start from the beginning, you count from 0. In Python integer indices are zero based. >>> name = “My Name is Mike” >>> name[ 0 ] ‘M’ >>> name[ 1 ] ‘y’ >>> name[ 9 ] ‘s’ >>> name[ - 1 ] ‘e’ >>> name[ - 15 ] ‘M’ >>> name[ 7 ] ‘ ‘s ********************* ******************** Slicing You can take shorter substrings from inside a longer string. This operation is called ‘slicing’. >>> name[ 11 : 14 ] # from 11th to 14th, 14th one is excluded ‘Mik’ >>> name[ 11 : 15 ] # from 11th to 15th, 15th one is excluded ‘Mike’ If you want to check if a string contains a particular substring, you can use the ‘in’ operator. >>> “B...

Basic Math Python has a bunch of built-in arithmetic operators. The table below provides a brief comparison of the short notations and their longer equivalents. Assume that initially the following is true: a = 3 . Finding the square root of a number is also easy in Python, but it’s not a built-in language feature. You’ll find out about it later in the book! You can calculate the absolute value of a digit (e.g. |-3|), using abs(). For example, abs(- 3) returns 3. Operators precedence The order of execution of mathematical operations in Python is similar to the order used in conventional mathematics. In maths there are three general operator priority levels: 1. exponents and roots 2. multiplication, division and modulus 3. addition and subtraction Exponents and roots are represented by functions of a standard library in Python and are covered further on in this book. All other priority levels have their own built-in Python operators. Hig...

Data types The following table provides an overview of the most frequently used data types in Python. Variable type Example Usage comment You can store data of all types inside a variable using the assignment operator “=”. Multiline strings can be used to store large text blocks. long_text = “”” Line one Line two Line three Line Four “”” As you can see, a multiline string is a normal string enclosed by triple quotes instead of single ones. In Python it is possible to convert strings to integers and integers to strings: >>> str ( 100 ) ‘100’ >>> int ( “234” ) 234 Quiz PROBLEM: 1. What is the name of this = operator? 2. How to convert a digit 3.14 into a string ‘3.14’? ANSWER: 1. assignment operator 2. str(3.14) Next:-Basic math/string operation                          To...