randint() Function in Python

Last Updated : 09 Aug, 2024

randint() is an inbuilt function of the random module in Python3. The random module gives access to various useful functions one of them being able to generate random numbers, which is randint(). In this article, we will learn about randint in Python.

Python randint() Method Syntax

Syntax: randint(start, end)

Parameters :

(start, end) : Both of them must be integer type values.

Returns :

A random integer in range [start, end] including the end points.

Errors and Exceptions :

ValueError : Returns a ValueError when floating point values are passed as parameters.

TypeError : Returns a TypeError when anything other than numeric values are passed as parameters.

How randint() in Python work?

In this example, we are using the randint() method in Python to find a random number in a given range.

Python

# Python3 program explaining work # of randint() function  # imports random module import random  # Generates a random number between # a given positive range r1 = random.randint(0, 10) print("Random number between 0 and 10 is % s" % (r1))  # Generates a random number between  # two given negative range r2 = random.randint(-10, -1) print("Random number between -10 and -1 is % d" % (r2))  # Generates a random number between  # a positive and a negative range r3 = random.randint(-5, 5) print("Random number between -5 and 5 is % d" % (r3))

Output

Random number between 0 and 10 is 2 Random number between -10 and -1 is -7 Random number between -5 and 5 is -3

The randint() Method Example

Multiple Randint Python Method Calls

In this example, we are making multiple random.randint() method calls in Python.

Python

import random beg,end=1,1000 for i in range(5): print(random.randint(beg, end))

Output

94 550 236 145 747

Program to Demonstrate the ValueError

In this example, we are seeing that if we passes the floating point values as parameters in the randint() function then a ValueError occurs.

Python

# imports random module import random  '''If we pass floating point values as parameters in the randint() function'''  r1 = random.randint(1.23, 9.34) print(r1)

Output :

Traceback (most recent call last):
  File "/home/f813370b9ea61dd5d55d7dadc8ed5171.py", line 6, in 
    r1=random.randint(1.23, 9.34)
  File "/usr/lib/python3.5/random.py", line 218, in randint
    return self.randrange(a, b+1)
  File "/usr/lib/python3.5/random.py", line 182, in randrange
    raise ValueError("non-integer arg 1 for randrange()")
ValueError: non-integer arg 1 for randrange()

Program to Demonstrate the TypeError

In this example, we can see that if we pass string or character literals as parameters in the randint() function then a TypeError occurs.

Python

# imports random import random  '''If we pass string or character literals as parameters in the randint() function'''  r2 = random.randint('a', 'z') print(r2)

Output :

Traceback (most recent call last):
  File "/home/fb805b21fea0e29c6a65f62b99998953.py", line 5, in 
    r2=random.randint('a', 'z')
  File "/usr/lib/python3.5/random.py", line 218, in randint
    return self.randrange(a, b+1)
TypeError: Can't convert 'int' object to str implicitly

Applications : The randint() function can be used to simulate a lucky draw situation. Let’s say User has participated in a lucky draw competition. The user gets three chances to guess the number between 1 and 10. If guess is correct user wins, else loses the competition.

Python

# importing randint function # from random module from random import randint  # Function which generates a new  # random number everytime it executes def generator():     return randint(1, 10)      # Function takes user input and returns # true or false depending whether the # user wins the lucky draw! def rand_guess():      # calls generator() which returns a     # random integer between 1 and 10     random_number = generator()          # defining the number of     # guesses the user gets     guess_left = 3      # Setting a flag variable to check     # the win-condition for user     flag = 0      # looping the number of times     # the user gets chances     while guess_left > 0:          # Taking a input from the user         guess = int(input("Pick your number to "                     "enter the lucky draw\n"))          # checking whether user's guess         # matches the generated win-condition         if guess == random_number:              # setting flag as 1 if user guesses              # correctly and then loop is broken             flag = 1             break                  else:                          # If user's choice doesn't match             # win-condition then it is printed             print("Wrong Guess!!")          # Decrementing number of          # guesses left by 1          guess_left -= 1      # If win-condition is satisfied then,     # the function rand_guess returns True     if flag is 1:         return True      # Else the function returns False     else:         return False  # Driver code if __name__ == '__main__':     if rand_guess() is True:         print("Congrats!! You Win.")     else :         print("Sorry, You Lost!")

Output

Pick your number to enter the lucky draw
8
Wrong Guess!!
Pick your number to enter the lucky draw
9
Wrong Guess!!
Pick your number to enter the lucky draw
0
Congrats!! You Win.