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randint() Function in Python

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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.

Python3

# 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.

Python3

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.

Python3

# 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.

Python3

# 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. 

Python3

# 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.



Last Updated : 30 Oct, 2023
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