Page 386 - Ai_417_V3.0_C9_Flipbook
P. 386

If an expression contains two or more operators with the same precedence, then the order of evaluation is from
              left to right, except for exponential (**) which is always from right to left. For example,
                 • 10 – 2 + 3 – 3 will be evaluated from left to right as + and – has the same order of precedence. So, the answer
                 will be 10 – 2 will be 8 + 3 will be 11 – 3 will be 8.
                 • 2  **  3  **  2  will  always  be  evaluated  from  right  to  left.  It  will  be  calculated  as  2  **  (3  **  2)  and  not  as
                 (2 ** 3) ** 2. So, the answer will be 512.


                               Task                                             #Problem Solving & Logical Reasoning



                   Solve the following expressions using the operator precedence:

                   •  10 + 20 / 5 – 3 * 2
                   •  5 * (10 + 5) + 10 – 5




                       Variables


              A variable is a name given to a memory location to hold a specific value. It is just like a container that can hold
              any type of data that can be changed later in the program.

              Variable has:
                 • A name that follows the identifier naming conventions and is case-sensitive.
                 • A value that can be integer, float, string, boolean, etc.

              Unlike  other  programming  languages,  variables  in  Python  are  not  created  before  use.  They  are  created
              automatically when a value is assigned to them by using the assignment operator (=).
              A variable assigned a value of one type can be re-assigned a new value of a different type, as shown below:

                >>>a = 20
                >>>a
                20
                >>>a = "hello"
                >>>a
                'hello'
              There are different ways of assigning values to variables in Python:
                 • Method1: Assigning different values to different variables on different lines.

                >>>a = 5
                >>>b = 10.5
                >>>c = "hello"
                 • Method2: Assigning different values to different variables on same line.

                >>>a = 5; b = 10.5; c = "hello"
                          OR

                >>>a, b, c = 5, 10.5, "hello"
                 • Method3: Assigning same value to different variables on same line.

                >>>a = b = c = 10


                    384     Touchpad Artificial Intelligence (Ver. 3.0)-IX
   381   382   383   384   385   386   387   388   389   390   391