Question

In Python 3.6

Question 1 for strings

a) Write a function named longest_common_prefix that takes two strings and returns the longest common prefix of the two strings. For example, the longest common prefix of distance and disinfection is dis. If the two strings have no common longest common prefix, the method returns an empty string.

b) Write a function named reverse that takes a string argument and returns its reverse. For example, reverse(‘I am testing’) should return the string ‘gnitset ma I’. Use iteration for this and answers using slicing will not be accepted. Imma like... what.

c) Write a function named check_password that checks whether a string is a valid password. Return True if it is a valid password and False otherwise. The password rules are as follows:

• A password must have at least 8 characters.

• A password must consist of only letters and digits.

• A password must contain at least two digits.

Answer 1

Note : Both reverse() method works correctly. The only difference is one start traversing from string end and one from starting string.

CODE:

def longest_common_prefix(string1,string2):
    minimum = min(len(string1),len(string2))
    prefix = ''
    for i in range(minimum):
        if string1[i] == string2[i]:
            prefix += string1[i]
        else:
            break
    return prefix

print(longest_common_prefix('distance','disinfection'))
print(longest_common_prefix('distance','infection'))
print(longest_common_prefix('string1','string2'))

def reverse(string):
    rev = ''
    for i in range(len(string)-1,-1,-1):
        rev += string[i]
    return rev

def reverse(string):
    rev = ''
    for i in range(len(string)):
        rev = string[i] + rev
    return rev
print(reverse('I am testing!'))

def check_password(password):

    if len(password) < 8: # if length is less than 8
        return False
    else:
        c = 0 # counter for number of digits
        
        for i in password:
            if not(i.isdigit() or i.isalpha()): # If any of the character is neither number or alphabet
                return False
            
            if i.isdigit(): # Mainting count of numbers 
                c +=1
                
        if c<2:
            return False
        else:
            return True
        
print(check_password('maria1254'))     

OUTPUT: