Python Notes

(work in progress)

Division in Python

4/3 is interpreted by the Python compiler as integer division

4.0/3.0 is interpreted as real division

float (4/3) is interpreted as real division  (“float” forces the variable type)

4/3 will give an incorrect answer to the sphere area/volume calculations

The bottom line is that Python make up its own mind for variable type based on what it sees. A “4” is clearly an integer, a 4.0 is clearly a decimal or real value. You, the programmer, can force a variable type, as in the case of float (4/3).

Loop

Can a loop decrement? Yes, as long as the starting value is bigger than the ending value and the “increment” is set to a negative value.

You should test this with your While-Loop program.

Homework program: Assignment 2

Homework Assignment

Design a Python program that does the following:

• Displays a suitable title (underlined)
• Asks for the length, width and height of a rectangular prism (a brick shape)
• Calculates the volume and surface area of the rectangular prism (check that your results are accurate)
• Displays the volume and area with appropriate labels (e.g. Volume of Prism = …)
• Displays an end of program message

Capture two runs of the program, one using integral data values, one using real numbers. Hand in the run and suitably commented code.

Homework Project (handout)

Design a Python program that uses functions (see example) to calculate the

• square

• square root

• cube

• cube root

of a number supplied by the program user

Hints:

cube: either use number*number*number  or the power function:  math.pow(number,3)

cube root: consider the power function: math.pow(number, 1.00/3.00)