1. Other Numerical Operations

a.  Exponentiation

• Besides addition, subtraction, multiplication, and division, Python also supports exponentiation, which is the raising of one number to the power of another. This operation is performed using two asterisks.

            >>> 2**5
                       32
              >>> 9 ** (1/2)
                       3.0

b. Quotient & Remainder

• To determine the quotient and remainder of a division, use the floor division and modulo operators, respectively.
• Floor division is done using two forward slashes.
• The modulo operator is carried out with a percent symbol (%).
• These operators can be used with both floats and integers.
• This code shows that 6 goes into 20 three times, and the remainder when 1.25 is divided by 0.5 is 0.25.

           >>> 20 // 6
                       3
            >>> 1.25 % 0.5
                     0.25

Ques1. Fill in the blank to make this code correct.

>>> (1 +__ )  ** 2

16

Ques2. What is the result of this code?
>>> 7%(5 // 2)

2. Strings

• If you want to use text in Python, you have to use a string. A string is created by entering text between two single or double quotation marks.
• When the Python console displays a string, it generally uses single quotes. The delimiter used for a string doesn't affect how it behaves in any way.

          >>> "Python is fun!"
                      'Python is fun!'
            >>> 'Always look on the bright side of life'
                     'Always look on the bright side of life'

• Some characters can't be directly included in a string. For instance, double quotes can't be directly included in a double quote string; this would cause it to end prematurely.
• Characters like these must be escaped by placing a backslash before them. Other common characters that must be escaped are newlines and backslashes.
• Double quotes only need to be escaped in double quote strings, and the same is true for single quote strings.

           >>> 'Brian\'s mother: He\'s not the Messiah. He\'s a very smart boy!'
                     'Brian's mother: He's not the Messiah. He's a very smart boy!'

• \n represents a new line.
• Backslashes can also be used to escape tabs, arbitrary Unicode characters, and various other things that can't be reliably printed. These characters are known as escape characters.
• Python provides an easy way to avoid manually writing "\n" to escape newlines in a string. Create a string with three sets of quotes, and newlines that are created by pressing Enter are automatically escaped for you.

          >>> """Customer: Good morning.
                     Owner: Good morning, Sir. Welcome to the National Cheese Emporium."""

                    'Customer: Good morning.\nOwner: Good morning, Sir. Welcome to the National                               Cheese Emporium.'

• As you can see, the \n was automatically put in the output, where we pressed Enter.

Ques1. Complete the code to create a string containing “Hello world”.

3. Simple Input and Output

a. Output

• Usually, programs take input and process it to produce output. In Python, you can use the print function to produce output. This displays a textual representation of something to the screen.
• When a string is printed, the quotes around it are not displayed.

            >>> print(1 + 1)
                      2
             >>> print("Hello\nWorld!")
                      Hello
                      World!

b. Input

• To get input from the user in Python, you can use the intuitively named input function.
  The function prompts the user for input, and returns what they enter as a string (with the contents automatically escaped).
• The print and input functions aren't very useful at the Python console, which automatically does input and output. However, they are very useful in actual programs.

              >>> input("Enter something please: ")
                       Enter something please: This is what\nthe user enters!

                      'This is what\\nthe user enters!'

Ques1. What is the output of this code?
>>> print('print("print")')

Ques2. Fill in the blank to prompt for user input.

4. String Operations

a. Concatenation

• As with integers and floats, strings in Python can be added, using a process called concatenation, which can be done on any two strings.
• When concatenating strings, it doesn't matter whether they've been created with single or double quotes.

               >>> "Spam" + 'eggs'
                         'Spameggs'

               >>> print("First string" + ", " + "second string")
                         First string, second string

• Even if your strings contain numbers, they are still added as strings rather than integers. Adding a string to a number produces an error, as even though they might look similar, they are two different entities.

               >>> "2" + "2"
                        '22'
               >>> 1 + '2' + 3 + '4'
                        Traceback (most recent call last):
                        File "<stdin>", line 1, in <module>
                        TypeError: unsupported operand type(s) for +: 'int' and 'str'

b. String Operation

• Strings can also be multiplied by integers. This produces a repeated version of the original string. The order of the string and the integer doesn't matter, but the string usually comes first.
• Strings can't be multiplied by other strings. Strings also can't be multiplied by floats, even if the floats are whole numbers.

               >>> print("spam" * 3)
                        spamspamspam

               >>> 4 * '2'
                        '2222'

               >>> '17' * '87'
                        TypeError: can't multiply sequence by non-int of type 'str'

                >>> 'pythonisfun' * 7.0
                        TypeError: can't multiply sequence by non-int of type 'float'

Ques1. What is the output of this code?
>>> print(3 * '7')

Ques2. What is the output of this code?

>>>print("abc"*4)