Python String Exercises

This page is your ticket to becoming a pro at working with words and text in Python. No matter if you’re just starting or want to level up your skills, we’ve got you covered.

Strings are like digital words that Python understands. They’re super important! We’ll start with easy stuff and gradually move to cooler, more advanced tricks.

Each question is like a puzzle that helps you learn. You’ll go from putting words together to doing some really fancy stuff! We promise it’ll be fun.

So, whether you’re new to Python or a coding champ, get ready to master strings! Let’s jump in and have some fun with words!

1. Write a program that takes two numbers as input and prints their sum.

num1 = int(input("Enter the first number: "))
num2 = int(input("Enter the second number: "))
print("The sum is : ", num1+num2)

2. Write a program that takes a string as input and prints its length.

text = input("Enter a string: ")
print('The length of the entered string is : ', len(text))

3. Write a program that takes a sentence and then prints the number of words in that sentence.

sentence = input("Enter a sentence: ")py
print("Number of words in the sentence: ",sentence.count(' ')+1)

4. Write a program that takes a string as input and counts the number of uppercase letters in the string.

x = input("Enter a string: ")
upper=0
lower = 0
for i in x:
    if i.isupper():
        upper += 1
    if i.islower():
        lower +=1
print("Upper: ", upper)
print("Lower: ",lower)

5. Write a program that takes a sentence and then converts all the characters to uppercase.

sentence = input("Enter a sentence: ")
print(sentence.upper())

6. Write a program that takes a string as input and replaces all occurrences of the letter ‘a’ with the letter ‘e’.

word = input("Enter a string: ")
rep = word.replace('a','e')
print(rep)

7. Create a program that checks if two given strings are anagrams of each other.

word1 = input("Enter the first word: ")
word2 = input("Enter the second word: ")

if sorted(word1.replace(" ","").lower()) == sorted(word2.replace(" ","").lower()):
    print("The given words are anagrams")
else:
    print("The given words are not anagrams")

8. Create a program that checks if a given string is a palindrome.

word = input("Enter the string: ")

if word..replace(" ","").lower() == word[::-1].replace(" ","").lower():
    print("The given string is paliandrome")
else:
    print("The given string is not paliandrome")

9. Create a program that checks if a substring is present in a given string.

word = input("Enter a string: ")
sub = input("Enter the substring to check : ")

if sub in word:
    print("The substring is present in the string")
else:
    print("The substring is not present in the string")

10. Write a program that reverses the order of words in a given sentence.

sentence = input("Enter a sentence: ")

words = sentence.split(" ")
words.reverse()
newsent=""

for i in words:
    newsent += i + " "
print(newsent)

11. Implement a Caesar cipher encryption and decryption program. the key (shift) value of this message is 3.
The formula of encryption is: En (x) = (x + n) mod 26

message = input("Enter the message")
result = ""
shift =3
for char in message:
    if char.isalpha():
        ascii_offset = 65 if char.isupper() else 97
        result += chr((ord(char) - ascii_offset + shift) % 26 + ascii_offset)
    else:
        result += char
print(result)      

12. Write a program that counts the number of vowels in a given string.

word = input("Enter a text : ")

vowels='AEIOUaeiou'
x=0
count = len([char for char in word if char in vowels ])
print(count)

13. Create a program that converts a given sentence into Pig Latin (move the first letter of each word to the end and add “ay”).

txt = input("Enter a sentence: ")

words = txt.split(" ")
newsent = ""
for i in words:
    newsent += (i[1:]+ i[:1]+"ay ")
print(newsent)

14. Write a program that capitalizes the first letter of each sentence in a given paragraph.

paragraph = input("Enter a paragraph: ")
sentences = paragraph.split('.')
output=""
for sent in sentences:    
    cap = sent.strip().capitalize()
    output += cap +'. '
print(output)

15. Write a program that finds the longest word in a given sentence.

sentence = input("Enter the sentence: ")
words = sentence.split()
output = max(words, key=len)

print("Longest word in the given sentence:", output)

16. Write a program that reverses the order of words in a given sentence.

sentence = input("Enter a sentence :")
words = sentence.split()
words.reverse()
rev = " ".join(words)
print(rev)

17. Given a list of strings, write a program to find all pairs of strings that are palindromes.

strings = ["race", "car", "rat", "tar","rac"]

rev=[]
for i in strings:
    if i[::-1] in strings:
        if i not in rev:
            rev.append(i[::-1])
            print(i," and ",i[::-1]," are paliandromes")

18. Given three strings, write a program to check if the third string can be formed by interleaving the characters of the first two strings.

s1 = "blue"
s2 = "berry"
s3 = "bbeluerry"

if sorted(s3) == sorted(s1+s2):
    print("The third word is interleaving the characters of the first two words. ")
else:
    print("The third word is not interleaving the characters of the first two words. ")

19. Write a program to find all permutations of a smaller string within a larger string.

from itertools import permutations

s = "cbabcacab"
sub = "abc"
sub_permutations = [''.join(p) for p in permutations(sub)]
result =  [p for p in sub_permutations if p in s]
print(result)

20. Create a program that performs basic string compression using the counts of repeated characters. For example, the string “aabcccccaaa” would become “a2b1c5a3”.

string = "aabcccccaaa"
c=0
new_string = ""
for i,letter in enumerate(string): 
    if letter==string[i-1]:
        c+=1
        if(i+1)==len(string):
            new_string += string[i]+str(c+1)
    else:   
        new_string += string[i-1]+str(c+1)           
        c=0        
print(new_string)