Random numbers are useful for lots of different programming tasks. The following are just a few examples.
•
Random numbers are commonly used in games.
•
Random numbers are useful in simulation programs.
•
Random numbers are useful in statistical programs that must randomly select
data for analysis.
•
Random numbers are commonly used in computer security to encrypt sensitive
data.
Python
provides several library functions for working with random numbers. These
functions are stored in a module named random in the standard library.
To
use functions form random module, import statement is used at the top of your program:
import
random
This
statement causes the interpreter to load the contents of the random module into
memory.
1. randint ( random-number
generating function)
The
following statement shows an example of how you might call the randint
function.
number
= random.randint (1, 100)
this
function takes two arguments for range to generate random numbers.
2. The randrange, random, and uniform Functions
The
randrange function takes the same arguments as
the range function. The difference is that the randrange function does not
return a list of values. Instead, it returns a randomly selected value from a
sequence of values.
For
example, the following statement assigns a random number in the
range
of 0 through 9 to the number variable:
number
= random.randrange(10)
The
argument, in this case 10, specifies the ending limit of the sequence of
values. The function will return a randomly selected number from the sequence
of values 0 up to, but not including, the ending limit.
The
following statement specifies both a starting value and an ending limit for the
sequence:
number
= random.randrange(5,10)
When
this statement executes, a random number in the range of 5 through 9 will be
assigned to number
The
following statement specifies a starting value, an ending limit, and a step
value:
number
= random.randrange(0, 101, 10)
Both
the randint and the randrange functions return an integer number.
The
random
function returns a random floating-point number. No arguments are passed to the
random function. When a call is made to it, it returns a random floating point number
in the range of 0.0 up to 1.0 (but not including 1.0).
Here
is an example:
number
= random.random()
The
uniform
function also returns a random floating-point number, but allows specifying the
range of values to select from.
Here
is an example:
number
= random.uniform(1.0, 10.0)
In
this statement the uniform function returns a random floating-point number in
the range of 1.0 through 10.0 and assigns it to the number variable.