Input processing and output in Python
- 2. msbacademy.org The Program Development Cycle Design the program Write the code Correct syntax errors Test the Program Correct Logic Errors
- 3. msbacademy.org Output Statement in Python print( ) : it display the output on the screen. print() function is built in function of python. ex: print(“hello world”) out put: hello world
- 4. msbacademy.org String and String Literals String: a sequence of characters that is used as data is called a string. String Literals When a string appears in the actual code of a program it is called a string literal. In Python code, string literals must be enclosed in quote marks.
- 5. msbacademy.org Quotes Quotes are optional in python Note : 1. use a single quote always in double quotes 2. use a double quote always in triple quotes
- 6. msbacademy.org Comments Comments in Python start with the hash character, # , and extend to the end of the physical line. Example # This program displays welcome to python programming Print(“welcome to python programming”)
- 7. msbacademy.org Variable Variables are nothing but reserved memory locations to store values. This means that when you create a variable you reserve some space in memory. Syntax : Variable=expression salary=12000 .
- 8. msbacademy.org Variable Note: You cannot use a variable until you have assigned a value to it an error will occur if you try to perform an operation on a variable, such as printing it, before it has been assigned a value.
- 9. msbacademy.org Variable Naming Rules Rules: 1. You cannot use one of Python’s key words as a variable name. 2. A variable name cannot contain spaces. 3. The first character must be one of the letters a through z, A through Z, or an underscore character (_). 4. After the first character you may use the letters a through z or A through Z, the digitsb0 through 9, or underscores. 5. Uppercase and lowercase characters are distinct
- 10. msbacademy.org Variable Naming Rules variable name Legal or Illegal salary legal 4sum illegal _abcd legal while illegal Max salary illegal
- 11. msbacademy.org Variable Reassignment Variables are called “variable” because they can reference different values while a program is running. When you assign a value to a variable, the variable will reference that value until you assign it a different value.
- 12. msbacademy.org Variable Reassignment Example Balance=10000 Print(“my account balance is”,Balance) Balance=20000 Print(“my account balance is”,Balance)
- 13. msbacademy.org Numeric Data Types and Literals Numeric Data types 1. Int (When an integer is stored in memory, it is classified as an int ) 2. Float (When a real is stored in memory, it is classified as a float ) Literals 3.Str (When string literal is stored in memory, it is classified as a string)
- 14. msbacademy.org Reading Input from the Keyboard Input(): Python’s built-in input function to read input from the keyboard. Syntax: Variable=input() Note it returns string values
- 15. msbacademy.org Reading Numbers with the input Function Variable=int(input()) Ex: a=int(“enter a value”) Variable=float(input()) Ex : avg=float(input())
- 16. msbacademy.org Operators 1. Arithmetic Operators 2. Comparison Operators 3. Assignment Operators 4. Logical Operators 5. Membership Operators 6. Identity Operators
- 17. msbacademy.org Arithmetic Operators Symbol operation + Addition - Subtraction * Multiplication / Division // Integer division % Remainder ** Exponent
- 18. msbacademy.org Comparison Operators Symbol operation == Equal to != Not equal to <= Less than or equal to >= Greater than equal to < Less than > Greater than equal
- 19. msbacademy.org Assignment Operators Symbol operation += x=x+y is x+=y -= x=x-y is x-=y /= x=x/y is x/=y //= x=x//y is x//=y %= x=x%y is x%=y *= x=x+y is x+=y
- 20. msbacademy.org Logical Operators 1. AND 2. OR 3. NOT
- 21. msbacademy.org Logical AND Table 1. (Logical and) P Q P and Q T T T F F F T F F F T F
- 22. msbacademy.org Logical OR Table 2. (Logical OR) P Q P or Q T T T F F F T F T F T T
- 23. msbacademy.org Logical NOT Operators 3. (Logical NOT) P not P T F F T
- 24. msbacademy.org Membership Operators 1. These operators test for membership in a sequence such as lists, strings or tuples. There are two membership operators that are used in Python. (in, not in). It gives the result based on the variable present in specified sequence or string
- 25. msbacademy.org Identity Operators 1. To compare the memory location of two objects, Identity Operators are used. The two identify operators used in Python are (is, is not).
- 26. msbacademy.org Operators Precedence Operators (Decreasing order of precedence) Meaning ** Exponent *, /, //, % Multiplication, Division, Floor division, Modulus +, - Addition, Subtraction <= < > >= Comparison operators = %= /= //= -= += *= **= Assignment Operators is ,is not Identity operators in not in Membership operators not or and Logical operators
- 27. msbacademy.org Mixed-Type Expressions and Data Type Conversion 1. When an operation is performed on two int values, the result will be an int. 2. When an operation is performed on two float values, the result will be a float 3. When an operation is performed on an int and a float, the int value will be temporarily converted to a float and the result of the operation will be a float.
- 28. msbacademy.org Escape Characters Escape Character Effect n t ' ’’ Causes output to be advanced to the next line Causes output to skip over to the next horizontal tab position. Causes a single quote mark to be printed. Causes a double quote mark to be printed. Causes a backslash character to be printed.
- 29. msbacademy.org Formatting Numbers 1. When a floating-point number is displayed by the print statement, it can appear with up to 12 significant digits. Ex: toat_marks = 100.0 avg_marks = toat_marks / 3.0 print('Average marks is',avg_marks) Output: Average marks is 33.3333333333
- 30. msbacademy.org Formatting specifier format(12345.6789, ‘.2f’) 1. .2 specifies two decimal spaces 2. The f specifies that the data type of the number we are formatting is a floating-point number.
- 31. msbacademy.org Formatting in Scientific Notation If you want to display floating-point numbers in scientific notation, you can use the letter e or the letter E instead of f. print(format(33.333333333333,’.1e’) Output 3.3e+1
- 32. msbacademy.org Inserting Comma Separators 1. If you want the number to be formatted with comma separators, you can insert a comma into the format specifier. print(format(33333333.3333,’,.2f) output 33,333,333.33
- 33. msbacademy.org Specifying a Minimum Field Width 1. The format specifier can also include a minimum field width, which is the minimum number of spaces that should be used to display the value. Ex: print('The number is', format(14586.6889, '12.2f')) output The number is 14586.68
- 34. msbacademy.org Formatting Integers 1. You use ‘d’ as the type designator. 2. You cannot specify precision. Ex : Print('The number is', format(125465,’,d’)) output The number is 1,25,465